Polskie Forum Astronautyczne

Artykuły o tematyce astronautycznej => Artykuły astronautyczne => Wątek zaczęty przez: Orionid w Lipiec 04, 2019, 00:00

Tytuł: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 04, 2019, 00:00
This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Mika McKinnon 3/05/2015

Sewing a replacement sunshield for the damaged Skylab. Left to right: Dale Gentry, Elizabeth Gauldin, Alyene Baker, and James H. Barnet Jr. Credit: NASA

When the Skylab orbital workshop was damaged on launch, it lost its sunshield and started overheating. This is a story of Alyene Baker saving the station, and a story of never underestimating the importance of being able to improvise with a sewing machine.

The Skylab orbital workshop was damaged during its uncrewed launch on May 14th, 1973. The lost micrometeorite shield also provided thermal protection: without it, the workshop was overheating. Before astronauts could live on the station, they needed to improvise a replacement.

Workers at the GE Building folding the sunshade. Left to right: Gerry E. Wood (wearing glasses), Glenn Hewitt, Pat Morrow, and Fred Le Donne. Image credit: NASA

The unexpected damage meant that Alyene Baker spent May 18, 1973 being assisted by a mix of GE and Johnson Space Center employees creating a replacement. In the GE building across the street from the Johnson Space Center, Baker sewed aluminum Mylar, rip-stop laminated nylon, and a bottom layer of thin nylon into a three-layered sunshield using a double-needle sewing machine.

The crew of Skylab 2 could easily identify the missing micrometeoroid shield visible and partially deployed solar array to the orbital workshop during their approach on May 25, 1973. Image credit: NASA

The replacement sunshield was folded and sent into orbit with the Skylab 2 crew. Astronauts Charles "Pete" Conrad, Jr., Joseph P. Kerwin, and Paul J. Weitz were originally scheduled to launch on May 15th, but were delayed until May 25th so they had the opportunity to practice repair techniques.

Astronaut Russell Schweickart developing a procedure to replace the damaged thermal protection cover. Image credit: NASA

Once the crew arrived at the station and took a break to eat, the highest-priority repair was to try and release a jammed solar panel to get the station back up to full power. Weitz used a 10-foot hooked pole to jab and tug at the array, while Kerwin held him steady. The efforts burned through a significant amount of Skylab's nitrogen manoeuvring fuel, and was totally futile.

Artist's concept of Conrad pushing up on the Beam Erection Tether in an attempt to free the stuck solar array. Image credit: NASA/Paul Fjeld

The next attempt was nearly two weeks later, when Conrad and Kerwin went on another EVA. This time they succeeded but with a jolt that flung them off the station, dangling at the ends of their safety tethers.

The bright orange replacement thermal shield was readily apparently to the departing crew on June 22, 1973. Image credit: NASA

After failing to repair the solar array on the day of their arrival, the astronauts tried to dock their craft to Skylab. The capture latches failed not once, not twice, but eight times when the frustrated astronauts finally partially disassembled the docking probe. Having finally gained entrance to the station, the astronauts stuck the improvised collapsible parasol through a smaller scientific airlock as a replacement sunshield. It deployed properly, fixing the problem and temperatures within the station were soon far more mangable.

The crew of Skylab 2 reflected on their repair job of rigging the orange parasol solar shield to act as a micrometeoroid and thermal shield when departing the orbital workshop on June 22, 1973. Image credit: NASA

The improvised sunshield replacement sewn by Baker and deployed by the crew of Skylab 2 was effective, stabilizing temperatures within the orbital workshop. It also added a bit of flare to the station, the wrinkly orange patch on the tin can station evoking a feeling of innovation and adaptation in keeping with the true spirit of space exploration.

Update: One of Baker's sons, Michael, has joined us in the comments with a bit more context, and a lovely reader has tracked down additional stories and photographs contributed by another of her sons, Herb.

Source: https://gizmodo.com/this-is-the-woman-who-replaced-skylabs-destroyed-sunshi-1689346849
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 06, 2019, 08:07
Attitude Control Game: Remembering Skylab's Fateful Launch, 45 Years Ago
By Ben Evans May 20th, 2018 [AS]

The Saturn V which launched Skylab was visually quite distinct from its predecessors. Although it possessed the S-IC and S-II first and second stages, the place of the third stage (S-IVB) was taken by the inert space station. Photo Credit: NASA

Forty-five years ago, this month, America almost lost its first space station. On the morning of 14 May 1973, the last in a generation of Saturn V boosters (https://www.americaspace.com/2017/11/05/without-breaking-the-shell-50-years-since-the-saturn-vs-maiden-launch/) sat on historic Pad 39A (https://www.americaspace.com/2017/11/12/pad-39a-americas-moonport-celebrates-over-100-launches-in-50-years-of-service/), ready for its journey into space. Visually, it was quite distinct from its predecessors, possessing two stages, instead of three, and in place of what would have been the final propulsive stage was Skylab, capped by a bullet-like aerodynamic shroud. To this day, the Saturn V remains the largest and most powerful rocket ever brought to operational status, and as it entered the final hours before its last launch, it could enjoy an almost unblemished reputation: its 12 previous missions had never failed to complete their primary objectives. The ominous, brewing clouds at Cape Kennedy carried much menace, but everyone knew the Saturn’s reliability: its muscle had sent men to the Moon on nine occasions, and for its final swan song there was every expectation that it would perform with perfection.

The behemoth Saturn had been sitting on the pad for a month, undergoing checks and countdown simulations. NASA was keenly aware that the success of Skylab was totally dependent upon the success of the launch, and if anything went awry it was unlikely that Congress would stump up the $250 million needed for another attempt. The station’s first crew—Commander Charles “Pete” Conrad, Science Pilot Joe Kerwin and Pilot Paul Weitz (https://www.americaspace.com/2017/10/24/paul-weitz-skylab-savior-and-inaugural-challenger-commander-dies-aged-85/)—were on hand to watch the station spear for the heavens and on the very next day, 15 May 1973, they expected to launch atop a Saturn IB rocket for a 28-day mission.

Precisely at 1:30 p.m. EST, the five mighty F-1 engines of the Saturn V’s first stage thundered to life, raising the question in everyone’s mind: had the rocket risen or had Florida sunk? Conrad had flown one of these mechanised monsters to the Moon and instinctively braced himself for the immense wave of sound that washed over him, the pummelling of the soles of his feet, and the intense vibration. At length, the lumbering Saturn cleared the tower and vanished into a deck of thick, iron-grey cloud, trailing an immense tongue of golden flame. Skylab was on its way.

The final Saturn V rolls out of the Vehicle Assembly Building (VAB) in early 1973, carrying America’s Skylab space station to the launch pad. Photo Credit: NASA

“It looked great,” Kerwin wrote in his book, Homesteading Space, and fellow Skylab astronauts Owen Garriott and Jack Lousma quickly headed to Patrick Air Force Base to pick up a T-38 jet for their return to Houston. Garriott and Lousma were due to fly the second mission to the space station in the late summer of 1973. As they walked towards their rental car, they happened to meet Rocco Petrone, head of NASA’s Marshall Space Flight Center, who advised them of “a few telemetry glitches.” The two astronauts did not ponder on Petrone’s words, and as they left Patrick and gained altitude, they had every hope that Skylab would soon be ready to accept its first astronaut visitors.

A minute after launch, the Saturn had gone supersonic and, shortly thereafter, passed through a period of maximum aerodynamic turbulence—nicknamed “Max Q”—during which atmospheric forces on the vehicle reached their most severe. It was a few seconds later that telemetry data indicated something was not right. The data almost went unnoticed, but indicated a premature deployment of Skylab’s protective micrometeroid shield and its No. 2 solar array. If the telemetry was for real, and was not an instrumentation error, it signalled very bad news and meant that both shield and array were as good as lost and the future of the mission thrown into doubt. For now, however, the assumption was made that it was nothing more than a spurious signal.

For a while, it seemed that the assumption was correct. The Saturn was flying perfectly, its second stage picking up the thrust for the final boost into low-Earth orbit, and at 1:40 p.m. the space station was released at an altitude of 430 km, about 1,800 km downrange of the Cape, high above the Atlantic Ocean. The bullet-like shroud separated and at 1:47 p.m. electric motors rotated Skylab’s massive Apollo Telescope Mount (ATM) out 90 degrees, locking it into place and deploying its windmill of four solar arrays. Before the mission, the successful deployment of the ATM had been a lingering concern…and it had been executed without a whimper. In the euphoria of those first few minutes in orbit, the mysterious bit of telemetry about the micrometeoroid shield and No. 2 solar array almost went unnoticed.

Bound for Skylab, the crew (from left) Paul Weitz, Joe Kerwin and Pete Conrad prepare for launch. Photo Credit: NASA


An hour later, Flight Director Don Puddy noticed erratic signals from the station. By that time, the solar arrays should have unfurled, but the data was confusing. Controllers expected their monitors to show both arrays producing around 12.4 kW—about 60 percent of Skylab’s electricity—but were dismayed to learn that power levels were much lower…a mere 25 watts! The data indicated that the arrays had released, but had not fully extended, whilst temperature levels implied that one of them had either been torn away or had suffered severe structural failure. A virtual absence of voltage supported this nightmare scenario. As engineers watched their data over the next few hours, they concluded that, indeed, the micrometeoroid shield had failed and a malfunctioning solar array had led to a power outage. Off-duty flight director Phil Shaffer quickly set to work on a “malfunction list” to handle all the problems which were now flooding into Mission Control…and quickly found himself with nearly 50 items, all of which were critical to the survival of Skylab!

The micrometeoroid shield had a secondary duty to provide thermal control; its external face carried a black and white pattern to absorb heat, whilst its internal face and the hull of the station itself were covered with gold foil to regulate the heat flow between them. As long as the shield stayed in place, the system would have kept Skylab on the cool side of the comfort zone…but now that it was gone, or disabled, the gold would begin to absorb heat and render the station uninhabitable. Sensors indicated external temperatures of 82 degrees Celsius (179 degrees Fahrenheit) and, inside, around 38 degrees Celsius (100 degrees Fahrenheit). Thermal engineers were already predicting that these would soon climb further, respectively, endangering the astronauts’ food stocks, camera film and perhaps even the physical structure of Skylab itself.

There were other dangers, too. Under such high temperatures, materials inside the station could “outgas”, producing contaminants which might suffocate a crew of astronauts. Lining the interior walls was a thick layer of polyurethane foam and fibreglass, one of whose constituents was a particularly nasty chemical, known as “toluene diisocynate”, which is today listed as one of the dozen most hazardous substances to human health. At temperatures of around 199 degrees Celsius (390 degrees Fahrenheit), it would begin to break down and release toxicity into Skylab’s atmosphere. In the days that followed, a set of gas-sampling tubes were prepared for Pete Conrad’s crew to measure the levels of toluene before entering the station.

Skylab’s precarious condition is evident in this image from Pete Conrad’s crew, revealing the tubing and wiring from the torn solar array at middle left. For several days, power came from the ‘windmill’ of arrays on the Apollo Telescope Mount (background). Photo Credit: NASA

Within eight hours, NASA canceled the scheduled 15 May launch of the first crew. The countdown clock, which had been halted at T-minus 14 hours and 35 minutes, was recycled to T-59 hours and held there, indefinitely. Based on Skylab’s orbital geometry, launch opportunities arose every five days and Conrad’s crew was rescheduled to fly no earlier than the 20th. The primary option at this stage was for the astronauts to fly a 17-day “nominal” mission and spend the final 11 days performing “minimal activity” to gather the required four weeks of medical data.

Yet even this plan was fraught with risk, as the situation aboard Skylab worsened. In order to produce electricity, the station had to remain in a “solar inertial” attitude, with the Sun’s rays perpendicular to the ATM panels…but this exposed the full length of the hull to excessive overheating. Mission Control reduced the problem for a while, by pointing the front end of the station directly towards the Sun, which lowered temperatures…but also caused power levels to drop precipitously. The best compromise, it was found, was to pitch Skylab “upwards” by about 45 degrees, towards the Sun. This allowed just enough sunlight to illuminate the ATM panels and charge their batteries, whilst also stabilizing internal temperatures at a balmy 42 degrees Celsius (107 degrees Fahrenheit). Conversely, temperatures in Skylab’s airlock now dropped and threatened to freeze heat exchangers and coolant loops by 18 May. Maneuvers to warm the airlock were successful, but at the expense of overheating the rest of the station.

The resultant problem of maintaining a fine balance between temperature and power proved incredibly difficult and intricate. Several of Skylab’s rate gyroscopes—needed for basic attitude control—overheated, whilst others produced random errors, and propellant was being used in far larger quantities than intended. “They played this attitude-control game for ten days,” wrote Joe Kerwin of the thermal engineers’ sterling efforts, “and hosed out a lot of the precious propellant on the workshop, which could not be replenished. I think we had used 60 percent of it by the time we arrived, after ten days.”

For the astronauts, that was a scary prospect, for Skylab was designed to spend a year in orbit, and support three crews for durations of up to three months. The arrival of Conrad and his men could not come soon enough…but before they could go anywhere, the first days of their mission and a whole plethora of repair methods would have to be developed and extensively tested. The speed and excellence with which that work was conducted transformed May 1973 from a month of despair into a shining example of NASA’s can-do spirit.

Source: http://www.americaspace.com/2018/05/20/attitude-control-game-remembering-skylabs-fateful-launch-45-years-ago/#more-104337
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 06, 2019, 08:17
'Tally-Ho the Skylab': The Mission to Save America's Space Station, 45 Years On (1)
By Ben Evans, on May 27th, 2018

The multiple docking adaptor and Apollo Telescope Mount (top left) of Skylab, viewed from the crew of the first visiting mission. Photo Credit: NASA

Four decades have now passed since one of the most dramatic reversals in fortune in American space history: the salvation of Skylab. On 14 May 1973, America’s first space station was launched into orbit atop the final Saturn V booster, but an unfortunate sequence of events led to the premature deployment of its micrometeoroid shield, which was promptly ripped away in the supersonic airstream, together with one of two solar arrays. The other solar array was so clogged with debris that it was “pinned” to the side of the station. For ten days, engineers battled to come up with a workable plan whereby Skylab’s first crew—Commander Charles “Pete” Conrad, Science Pilot Joe Kerwin and Pilot Paul Weitz—could effect a successful repair and keep the crippled station on the straight and narrow.

With a cry of “We can fix anything”, the first crew heads toward Skylab on 25 May 1973. Since the launch pad was originally configured for the enormous Saturn V rocket, the smaller Saturn IB required a ‘pedestal’ to raise its stages to the appropriate level for umbilicals and other utilities. Photo Credit: NASA

With their launch scheduled for the stroke of 9 a.m., the morning of 25 May was particularly peaceful for the three astronauts. “This was the least well-attended Apollo launch in history,” Joe Kerwin recalled, “because everybody had to go home and put the kids back in school. We arrived at the command module and looked inside and it was a sea of brown rope under the seats and under the brown ropes were all these different umbrellas and parasols and sails and also the equipment that we had selected to try and free up the solar panel, which was a pretty eclectic collection of aluminum poles that could be connected together, and a Southwestern Bell Telephone Company tree-lopper with brown ropes to open and close the jaws. Some of it we’d seen, some of it we hadn’t!”

The astronauts were unperturbed. Indeed, as the Saturn IB cleared the tower and roared into the clear morning sky, Conrad declared that his crew could fix anything. Launch came precisely on time and kicked off an eight-hour orbital ballet to rendezvous with the crippled Skylab later that same afternoon. Little did anyone know that the first day in space for Pete Conrad and his crew would run to no less than 22 hours…

The first view of Skylab in orbit was disheartening for Pete Conrad, who had headed the astronaut office’s Skylab Branch (and been nicknamed ‘Sky King’) since 1970. One solar array was gone, the other was jammed and the lost micrometeoroid shield placed any prospect of a successful repair in jeopardy. Photo Credit: NASA

Conrad’s call of “Tally-ho the Skylab!” as a steadily brightening star on the horizon drew closer masked, at first, the seriousness of what the astronauts were about to face. The micrometeoroid shield was gone, as was one of the two solar arrays, whilst the second was so jammed with debris that it could not deploy properly. As Weitz took pictures, Conrad performed a flyaround inspection of the station, quickly ascertaining that the scientific airlock was not cluttered with debris, thereby making the deployment of the Johnson Space Center’s specially-conceived parasol a realistic option, and asserting his conviction that a stand-up EVA with the cable cutter should be enough to free the jammed solar array.

The first order of business was a “soft docking” at Skylab’s forward port at 5:56 p.m., engaging capture latches but not retracting the command module’s docking probe to ensure a firm metallic embrace. For a few minutes, the astronauts ate a quick dinner and prepared for the stand-up EVA. “A full hard dock wasn’t desirable at this point,” wrote David Hitt, Owen Garriott and Joe Kerwin in their book Homesteading Space, “because of the likelihood that they’d undock again shortly. The docking system needed to be dismantled and reset after a hard dock.” With all three men fully suited, Conrad undocked from Skylab at 6:45 p.m., depressurized the cabin, and opened the side hatch. With Kerwin hanging onto his ankles to provide stability, Weitz reached out and used modified tree loppers and a kind of “shepherd’s crook” to free the jammed array. It should have been an occasion of euphoria for Weitz, who had not been scheduled to perform an EVA at all on this mission. Unfortunately, despite his sterling efforts, it did not go well.

Skylab’s precarious condition is evident in this image from Pete Conrad’s crew, revealing the tubing and wiring from the torn solar array at middle left. For several days, power came from the ‘windmill’ of arrays on the Apollo Telescope Mount (background). Photo Credit: NASA

At first, he positioned himself with his upper body poking through the hatch. Kerwin passed him three sections to assemble a 15-foot (4.5-meter) pole with the loppers at the end, whilst Conrad kept the spacecraft steady. “We had seen…that there was a piece of bolted L-section from the thermal shield that had been wrapped up around the top of the solar wing,” Weitz recalled in his oral history, “and apparently the bolt heads were driven into the aluminium skin. We thought maybe we’d just break it loose, so we got down near the end of the solar array and I got a hold of it with the shepherd’s crook.” However, as Weitz heaved on it, he was actually pulling the command module towards Skylab. In the meantime, Conrad had the unenviable task of keeping the spacecraft close to the station and preventing the unwanted oscillations from causing a collision. The work was harder because a third of his field of view was blocked by the command module’s open hatch.

“It made for some dicey times,” Weitz later recalled. As the two vehicles entered orbital darkness, he paused in his work, then resumed as they flew within range of the tracking station. The shepherd’s crook was getting him nowhere and the torrent of four-letter words from all three astronauts even prompted the capcom in Mission Control to ask them to modify their language; for they were on an “open mike”.

Joe Kerwin at work during the critical EVA task to repair Skylab. Photo Credit: NASA

The main problem, Conrad explained, was that a strip of metal had become wrapped across the solar array during the separation of the micrometeoroid shield. Its bolts had tangled themselves in the array and none of Weitz’s actions to cut the strap, even with the loppers, were having any effect. “Rather than cutting it across the short way, we were trying to cut along the long way,” Weitz said, “and didn’t have enough muscle with that thing, because it was six or eight feet out ahead of me and I was pulling on a line to try to do it.” The metal strap, ironically, was only a few centimetres wide, but it was riveted fast and Conrad knew they did not have a hope of breaking it using the tools in the command module.

The attempt was scrapped and, after 40 minutes, the astronauts were instructed to close the hatch and re-dock with Skylab. Even this proved easier said than done: getting the pole, loppers, and shepherd’s crook back inside in a safe and speedy manner led to an inadvertent thump to Conrad’s helmet and an accidental kick to Kerwin. The capcom’s advice to modify their language again fell on deaf ears, as a few more “unscientific” words were uttered.

Prolonged solar exposure had already caused Skylab’s outer skin to blister, as evidenced by this image from Pete Conrad’s mission. The scientific airlock aperture through which the parasol was extended is clearly visible. Photo Credit: NASA

On their first docking attempt, the probe did not engage with the drogue and no fewer than three further tries were also fruitless. “Pete gave Weitz the controls,” Nancy continued, “depressurised the command module, and opened the tunnel hatch. He and Joe dove head-first into the bank of circuits and gizmos, Pete cussing a blue streak as he sorted through wires, cutting and splicing like a pissed-off Maytag repairman trying to get a dryer to work again.” Weitz then set about rewiring in the right-hand equipment bay, removing the electrical inter-lock which prevented the main latches from actuating until the capture latches were secure. After an hour or so of re-routing and connecting wires, bypassing electrical relays for the capture latches on the tip of the probe, skinning knuckles—and another bout of undesirable vocabulary—Conrad used the service module’s thrusters to bring the two collars into direct contact, triggering a dozen capture latches in a cacophony like machine gunfire.

They were at Skylab to stay.

In their oral histories, both Kerwin and Weitz paid tribute to a conversation with their rendezvous instructor, Jake Smith, in February 1973, in which the minutiae of how to accomplish this kind of “backup docking procedure”—which wires to cut and which to splice together—had been explored. Had it failed, there was a very real possibility that the mission would have ended. Now, though, with Apollo safely docked, an ecstatic Mission Control were able to advise the crew to grab a bite to eat and some sleep before entering Skylab the following morning. Their first day in space had been a long one—more than 22 hours, prompting Paul Weitz to quip that “union rules wouldn’t allow us to work that long anymore!” Surprisingly, neither of the rookies had gotten sick. Joe Kerwin had taken a pill shortly after reaching orbit, determined that he would not throw up and would not screw up the mission, but both he and Weitz adapted well to the weightless environment. Making his fourth space mission, Pete Conrad had no problems whatsoever.

In the hectic ten days between the launch of Skylab and the launch of Pete Conrad’s crew, NASA and its contractors rose spectacularly to one of the greatest challenges in their history. In the water tank at the Marshall Space Flight Center, astronauts Rusty Schweickart and Ed Gibson practice repair techniques. Photo Credit: NASA

Next morning, the crew opened the hatch and Weitz, as the systems specialist, was the first to enter Skylab. Pressure checks and air sampling gave the atmosphere a clean bill of health. The multiple docking adaptor and airlock were cool, at just 13 degrees Celsius, but all three men knew that the unprotected interior of the station would be hotter and less comfortable. Conrad and Weitz stripped “down to our skivvies” and opened the hatch into the darkened workshop to deploy the parasol through the scientific airlock. “It didn’t take very long until we figured out why people in the Sahara Desert wear a lot of loose clothing,” reflected Weitz, “because soon we had long trousers on and shirts and jackets and hats and gloves and the whole thing.” The temperature was 55 degrees Celsius (131 degrees Fahrenheit)—“rather warm,” the two men noted—and although there was no evidence of toxic gas and the air was safe to breathe, Skylab’s humidity was low and they could only remain inside the stifling oven for 15 minutes at a time. Periodically, they had to retreat back to the relative comfort of the multiple docking adaptor for a breather.

At length, the parasol was assembled and its rods were threaded through the aperture of the scientific airlock into vacuum. Next, the parasol emerged, folding out like a big patio umbrella. However, one of its four folded arms did not swing out properly and Kerwin, watching from inside the command module, expressed dismay when he saw it had only deployed to cover two-thirds of its required area. “It’s not laid out the way it’s supposed to be,” a dejected Conrad told Mission Control. The parasol was askew and crinkled in places. Nevertheless, Houston assured the astronauts that the wrinkles had probably set in during the coldness of the lengthy deployment, which took place during orbital “night-time” and, as the material heated up in sunlight, it would spread out fully.
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 06, 2019, 08:18
'Tally-Ho the Skylab': The Mission to Save America's Space Station, 45 Years On (2)

Clogged with debris, Skylab’s sole surviving solar array was left pinned to the side of the station. This view from the first crew illustrates the daunting nature of the problem. Photo Credit: NASA

“I think the ground noticed the temperatures coming down,” Weitz recalled. “Within an hour, they could tell.” Overnight on 26/27 May, temperatures on the exterior of Skylab began to fall. Eventually, the interior temperature stabilised at around 30 degrees (86 degrees Fahrenheit) and the astronauts could even tell where the parasol lay on the outer hull, by running their hands along the inner wall and feeling the difference in temperature. For the first couple of nights, Conrad and Kerwin elected to sleep in the command module, whilst Weitz tied his sleeping bag in the multiple docking adaptor, “because it was cooler there and you had a lot more room besides.” Scientific work could now begin, although electrical power remained an issue and was rendered more acute when the Apollo Telescope Mount (ATM) arrays were taken out of direct sunlight on 30 May, leaving Skylab reliant upon battery power.

An EVA was needed to fix the clogged array. Under the direction of backup commander Rusty Schweickart, a repair scenario was devised. It required Conrad and Kerwin to move to the antenna boom at the forward end of Skylab and attach a cable cutter to the debris; this would serve as a makeshift “hand rail” to enable them to reach the jammed solar array and cut the metal strap. Once there, they would have to break a frozen hydraulic “damper” on the array. The damper’s purpose had been to prevent the array from deploying too fast, but when it partially unlatched after launch, the hydraulic fluid quickly froze solid. Conrad and Kerwin would connect a Beam Erection Tether (BET) between the array and the airlock. When the debris had been removed, it was hoped that pulling on the tether would break the damper.

During a series of simulations on 2 June, Schweickart and fellow astronaut Ed Gibson practised the procedure and found that, aside from a lack of foot restraints, it was workable.

Paul Weitz, pictured at Skylab’s Apollo Telescope Mount (ATM), during his 28-day mission in May-June 1973. Photo Credit: NASA

The lack of foot restraints, and lights, hand-holds, and visual aids, was not an oversight; it reflected the fact that there had never been any intention to perform maintenance on Skylab. There were several planned EVAs, for example, to replace film cassettes, but actual repairs were considered too dangerous. “I had been working a lot of the spacewalk procedures for the film retrieval,” Gibson told the NASA oral historian, “so it was natural to then start developing procedures for the repair of the station”.

However, some managers remained jittery about the idea of attaching a cable cutter to debris, but there was little alternative. On the evening of 4 June, Schweickart talked Conrad through the task and, as the astronauts slept, a list of tools and assembly instructions were transmitted to Skylab’s teleprinter. The crew reviewed these procedures and rehearsed the steps inside the station on 6 June, with a suited Kerwin, minus his helmet, practicing the movement of the poles and grabbing a mock target with the cutters, before finally venturing outside in the early hours of the following morning.

Since the airlock was in the middle of the Skylab “cluster”, the fully-suited Weitz had to ensure that Conrad and Kerwin had all of their tools and tethers before he depressurised them. Weitz then retreated into the multiple docking adaptor. Conrad assembled the tools—six rods screwed together, the cable cutter fitted, and rope from the backup sail tied to the cutter’s pull rope—and then he and Kerwin moved into position alongside the antenna boom. The unlikely contraption thus enabled them to operate the cutter from several metres away…just enough to reach the jammed array.

As Kerwin tried to close the cutters against the debris, it became apparent that he was “slipping”, because he could not establish a secure position for himself. For half an hour, with one hand steadying himself and the other trying to close the cutters, he struggled fruitlessly to complete the work. As his pulse rate began to climb, he decided on an alternative course of action and shortened his own tether, in an effort to steady himself against the edge of the station. It worked and after ten minutes he was able to tell ground controllers that the cutters were securely fastened to the debris. Next, he pulled on the lanyard to operate them, but nothing happened. Conrad inched his way, hand-over-hand, along the length of the beam to see what was amiss, and precisely as he reached the cutter “end,” the jaws snapped shut, freeing some of the metal strap and hurling him “ass over teakettles” into space. Fortunately, Conrad’s tether restrained him from moving far from Skylab, and the jammed array now stood at 20-degrees-open.

The salvation of Skylab, perhaps more so than any previous endeavor, validated the importance of Extravehicular Activity (EVA). Photo Credit: NASA

The frozen damper, however, still resisted normal deployment and the holes on the solar array were smaller than on the ground model, so he could only attach one of the two hooks on the BET. The two men heaved on the tether, but without success, until Conrad placed his feet on the frozen hinge, stooped to fit the tether over his shoulder and “stood up.” Kerwin pulled on the tether and, this time, the solar array suddenly released and sprang into its full, 90-degrees-open position. Both astronauts were flung outwards by the catapult-like effect and arrested by their tethers. After 3.5 hours, the two laughing astronauts re-entered Skylab and the needles of the electricity meters dramatically jumped, signaling success.

By the next day, 8 June, solar heating had fully extended the array and it was generating 7 kW of much-needed power. From just 40 percent power, the station’s output suddenly increased to around 70 percent. NASA’s confidence in the abilities of spacewalking astronauts increased substantially. “Before that, there was still the legacy of problems with EVA during Gemini,” recalled Rusty Schweickart. “Apollo, of course, made a big difference, but that was sort of running around on the [lunar] surface in gravity again; so here was EVA of a massive scale in weightlessness that we never anticipated; [we] did it with flying colors, everything worked just fine, never had a problem and saved the mission.”

Saving Skylab was a personal triumph for Pete Conrad. Between May 1973 and February 1974, three crews would occupy the station for as long as three months at a time and would contribute enormously to humanity’s understanding of the weightless environment and the influence of the Sun upon our planet. Conrad’s first three space missions had each been filled with drama—a record-breaking Gemini flight, which exceeded the Soviets for the first time, an intricate orbital rendezvous, and an adrenaline-charged lunar landing—but it was for none of these that he received the Congressional Space Medal of Honor in 1978. It was Skylab which propeled him to his greatest professional height and his greatest personal accomplishment and the Congressional accolade paid tribute to Conrad’s devoted command of the singular mission which saved America’s first space station.

Source: https://www.americaspace.com/2018/05/27/tally-ho-the-skylab-the-mission-to-save-americas-space-station-45-years-on/
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 07, 2019, 08:11
A Sick Crew and A Sick Ship: The Trials of Skylab 3 (Part 1)
By Ben Evans, on July 27th, 2013 [AS]

Pictured during the rendezvous procedure, this view clearly shows Skylab’s multiple docking adapter, equipped with twin ports to support a visiting craft and a possible rescue craft. Photo Credit: NASA

Forty years ago this summer, America’s first space station—Skylab—was boosted into orbit atop the last in a generation of mighty Saturn V rockets. During launch, however, disaster struck the mission, when the station’s micrometeoroid shield and one of its electricity-generating solar arrays were torn away in the aerodynamic slipstream and the first crew were faced with enormous difficulty to turning Skylab from a barely habitable hulk into their home for a month. They returned to Earth in late June 1973, leaving a vastly improved station (https://www.americaspace.com/2013/05/18/with-flying-colours-the-revival-of-skylab/) for the next crew. On the second mission, Skylab 3, astronauts Al Bean, Owen Garriott, and Jack Lousma were tasked to spend a record-setting 59 days in orbit, more than twice as long as had been accomplished by any previous astronaut or cosmonaut. The mission would prove an enormous success … but that success could hardly have been imagined during Skylab 3’s first few unfortunate days.

Everything seemed to be looking up for Bean, Garriott, and Lousma. On 20 July, a week before launch, their mission was extended in length from 56 to 59 days to provide a better recovery posture for their scheduled return to Earth and splashdown in late September. One of the biggest worries facing the new crew was the health of Skylab’s stabilizing rate gyroscopes, needed for orientation, and the possible deterioration of a makeshift “parasol,” fitted by the first crew. For its part, NASA was so keen to get Bean and his men aboard the station as quickly as possible that on 6 June—while the first crew were still in residence—the launch of the second mission was advanced a week from early August to 27 July, with an option to fly on the 22nd if the situation worsened.

As these plans crystallised, the Saturn IB rocket and the attached command and service modules were rolled out to the Kennedy Space Center’s Pad 39B on 11 June. A series of inauspicious lightning strikes on the launch tower raised a few eyebrows, but the damaged parts—including spacecraft instrumentation—were replaced and retested. The countdown commenced on the morning of 25 July, with launch set to occur at the start of a ten-minute “window,” opening at 7:08 a.m. EDT on the 28th.

Launched atop the final Saturn V - configured slightly differently with a bullet-like aerodynamic payload shroud - the mission of Skylab almost ended before it had even begun. Forty years ago, this summer, astronauts brought America's first space station back from the brink. Photo Credit: NASA

In orbit, Skylab had been carefully depressurized and its internal temperature was kept at a controlled level to prevent condensation whilst unoccupied. Solar observations were also pursued, autonomously, using the Apollo Telescope Mount (ATM), although this work was suspended following the failure, on 19 July, of a primary rate gyroscope—one of the nine electronic instruments used to provide primary and backup control of the station’s orientation in the roll, pitch, and yaw axes. Four days later, NASA announced that Bean’s crew would carry a “six-pack” of replacement gyros (properly termed a “rate gyro augmentation package”) to provide redundancy for both their mission and that of the final crew.

“At present,” NASA reported, “one [gyro] has been turned off because it malfunctioned, while five others have overheated to some degree at one time or another during more than two months the spacecraft has been in orbit.” The news release cautioned that an actual replacement would probably not happen unless all three gyros failed in one axis, requiring approximately 20 minutes of EVA time. Also aboard the command module was an improved parasol. The astronauts had trained extensively to install both this and the Marshall Space Flight Center’s twin-pole thermal shield, which had been developed in May to provide backup micrometeoroid protection and supplement the parasol and had been taken to the station by the first crew, but not deployed.

Twenty hours before the crew was set to lift off, Skylab’s atmosphere was repressurized, in anticipation of the arrival of its second team of human visitors. Despite its very long duration, Bean’s mission would be packed to the rafters with scientific and engineering objectives: a preliminary timeline, released by NASA on 12 July, highlighted plans for an EVA on the 31st, in which film canisters would be loaded for the ATM and the twin-pole sunshade would be installed. Two more excursions were also scheduled for 24 August and 19 September for the purposes of retrieving and installing more ATM film.

If Skylab was ready for an influx of new arrivals, then the Kennedy Space Center was equally ready and received its own fair share of visitors on the day of launch, with no fewer than 35,000 people cramming the press site, public viewing areas, and causeways, excited by the drama of the last several weeks and eager to observe the next part of the adventure. The morning of 28 July dawned dreary and overcast, evidenced by NASA television footage from the day, with only a few lights in the vicinity of the pad twinkling through the gloom and illuminating the ghost-like shape of the Saturn IB.

Commander Al Bean leads his men out of the Operations & Checkout Building on the morning of 28 July 1973. Their first few days in space would be filled with much drama. Photo Credit: NASA

Aboard the command module, Bean was positioned on the left, with science pilot Garriott in the centre seat and pilot Lousma over on the right. During training, they had convinced themselves that all three of them came from the U.S. Navy—Bean was an active captain in the service, Lousma a major in the Marines (which “really is just a subset of the Navy,” according to Garriott), and the science pilot himself was a veteran of three years of naval duty in his younger days. “My total time in the military,” Garriott acquiesced, “hardly compared to the career that both Alan and Jack have, but that was a minor unifying factor and we had a chance to joke about it from time to time.”

By the time he ascended the tower to Pad 39B for his first launch into space, Garriott had been training almost exclusively on Skylab for more than five years and knew his two crewmates not only as colleagues, but as friends. All too often, the perception of Garriott as the “science pilot” on the mission has led many observers to assume that the duties of his colleagues were exclusively piloting or engineering roles. The reality was that all three men were cross-trained and each was as competent and internally motivated as the others to accomplish Skylab’s scientific objectives. Their deep-seated friendship persisted and, even three decades after their mission, they took family holidays together.

When the astronauts arrived at the pad for their launch into space, Lousma still had to pinch himself. Clambering into the transfer van in his bulky space suit and oxygen hoses, he had to constantly remind himself that this was not a simulation or a drill; it was the real thing. The flashlights of the assembled press were for real, as were the checkpoints, the last-minute examinations by the flight surgeon, the traditional astronaut’s breakfast of steak and eggs, the sticking of biomedical electrodes to their chests, and the pressure checks of their space suits. “The technicians … weren’t saying much of anything,” Lousma recalled in his NASA oral history, “because I think they were afraid they would disturb you. You could tell that they knew that this was the moment of truth, and it was quite clear that this was the day we were all waiting for.”

Out on the gantry of Pad 39B, awaiting his turn to board the command module, Lousma noticed that the normal beehive of activity and the dozens of hard-hatted technicians who normally swarmed around were conspicuously absent; the launch complex was eerily quiet, with hardly any sound, save for the hissing airflow inside his helmet. “Boy, this was the absolute 2001 experience,” Lousma said. “This was really spacy.” As the science pilot, occupant of the command module’s centre seat, Garriott was the last to enter and had a few moments of private reflection, gazing across the slumbering Florida landscape. “There was a long training period leading up to this moment,” he recalled. “A fiery rocket would soon take our speed from zero to over five miles a second … in less than ten minutes!”

Mounted atop a “milk stool” to elevate it to the proper level for Pad 39B’s umbilicals, the Saturn IB carrying Bean, Garriott, and Lousma begins its journey toward Skylab. Photo Credit: NASA

From the press site, several kilometres away, CBS anchorman Morton Dean was relaying live commentary to his audience. Next to him sat former Apollo astronaut Wally Schirra, now the network’s “special expert consultant.”

“T minus 40 seconds,” Dean intoned, as television images showed the Saturn IB, scarcely visible against the murk of the early morning. A few twinkling searchlights glimmered through the pre-dawn gloom. “The spacecraft commander has now made the final guidance alignment,” he continued. “That’s the final action to be taken by the crew on-board the spacecraft until after the launch. T minus 30 seconds … the eight first-stage engines will ignite at 3.1 seconds in our countdown. They’ll be held down while thrust is built up at the zero mark, at which time we’ll get liftoff.”

Morton Dean’s voice notched up an octave as he prepared his audience for the big event and those final few seconds before the Saturn was set to shear its manacles and tear itself loose from Earth: “T minus ten, nine, eight, seven, six, five, four”—then a tongue of bright orange flame, which steadily thickened and expanded into a vast, blinding sheet, erupted from the base of the booster and licked at the metallic trusses of the rocket’s supporting milk stool—“three, two, we have ignition sequence start, all engines are running”—as the eight H-1 engines roared to near-full power, almost obscuring the rocket from view with their glare—“we have a liftoff … and the second manned crew has cleared the tower!”

As the Saturn rose into the overcast sky and quickly vanished into a deck of gloomy, lowering cloud, Dean turned to Schirra and chattered over the airwaves about his impressions of the launch: the rolling thunder and pulsations of sheer naked energy which now pummelled their bodies.

From his couch on the right side of the command module, Lousma noticed a very definite “heavy vibration” at the instant of liftoff. This sensation very quickly damped out, but the initial “chugging” of the Saturn IB did little to disguise the tremendous acceleration, which peaked at around four and a half times the force of gravity. As the S-IB first stage expended its load of propellant and separated, the three men were greeted by an eerie, though temporary, silence, as they coasted for a while, interrupted by the detonations of explosive charges, then the seat-of-the-pants push as the single J-2 engine of the S-IVB took over and continued the boost into orbit. Through the window, Lousma vividly remembered seeing a vast, circular “fan” of debris, flying outwards in all directions and glinting in the sunlight. For Owen Garriott, the sensation of being pressed into his seat at several times his Earthly weight to suddenly floating in his harness was electrifying.

Ten minutes after leaving Florida, the second Skylab crew were in space, primed for an eight-hour chase of Skylab and a late-afternoon rendezvous and docking. Also hitching a ride to their new orbital home was one of the largest “crews” ever launched; for in addition to Bean, Garriott, and Lousma, a complement of almost 800 living creatures were packed into various nooks and crannies and lockers and containers within the command module. Their purpose was to permit researchers to analyse circadian rhythms and closely monitor how they would cope and adapt to the strange weightless environment. The astronauts would share their home with two common cross spiders (Araneus diadematus), named Anita and Arabella, together with a pair of brackish water minnows (colloquially known as “Mummichogs”) and 50 of their eggs, half a dozen pocket mice from the deserts around Palm Springs, Calif., and 720 vinegar gnat pupae.

The fish, NASA revealed, had been added to the list at Garriott’s request and were caught in the coastal waters near Beaufort in North Carolina. Their presence in a specially-built aquarium was part of vestibular studies into the possible disorientating effect of weightlessness, whilst Anita and Arabella—part of a student experiment proposed by 17-year-old Judith Miles—would be monitored to assess their ability to build webs in conditions utterly peculiar to those in which their species had evolved. Lastly, the mice and gnats were kept in a compartment aboard the service module and were part of investigations into changes of circadian rhythms.

In spite of a seemingly perfect launch and insertion into orbit, problems did not take long to catch up with the crew. About three hours after leaving Cape Canaveral, midway through their orbital ballet to rendezvous with Skylab, Bean reported what he described as “some kind of sparklers” streaming past one of the command module’s windows after the first firing of the big Service Propulsion System (SPS) engine. Lousma had spotted it first and called Garriott to his window on the right side of the spacecraft to take a look. “I looked out his window,” Garriott recalled, “and here came what looked to be the nozzle of one of the reaction control thrusters just floating by the window! It couldn’t have come off the spacecraft … the propellant line to that nozzle had sprung a leak, so when the propellant comes out of the fuel line, it then freezes on the nozzle and then after a certain amount of it escapes, it acquired the shape of the nozzle. What floated away was an ice sculpture of that reaction control thruster!”

A few seconds later, Bean was startled by the blaring of a master alarm, which indicated low temperatures in one of the ship’s Reaction Control System (RCS) thruster quads. And at this stage, the problems of Skylab 3 really began to take hold.

Source: https://www.americaspace.com/2013/07/27/a-sick-crew-and-a-sick-ship-the-trials-of-skylab-3-part-1/
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 07, 2019, 08:11
A Sick Crew and A Sick Ship: The Trials of Skylab 3 (Part 2)
By Ben Evans, on July 28th, 2013 [AS]

Although Skylab was operational by the time that Al Bean’s crew arrived, its damaged exterior was still obvious. Note the presence of only one electricity-generating solar array. Photo Credit: NASA

Within hours of reaching orbit, on 28 July 1973, the attention of Bean and his men was captured by the blaring of the command module’s master alarm. It alerted them to unusually low temperatures in one of the Reaction Control System (RCS) thruster quads. All three men realized that a leak of either hydrazine fuel or nitrogen tetroxide oxidiser had most likely occurred in “Quad B,” one of four sets of RCS thrusters, spaced at 90-degree intervals around the circumference of the service module. It was not good that it had come during the rendezvous with Skylab and so early into their mission. They quickly set about shutting down the entire quad on Lousma’s side of the spacecraft. Data telemetered to the ground revealed a clear drop in pressure, as both the hydrazine and pressurizing helium rapidly fell to off-scale lows.

In the book Homesteading Space, co-authored by Garriott, it was noted that the “reduced authority” of having only three sets of available RCS quads meant Bean had to pulse the remaining thrusters for longer to achieve a perfect rendezvous with Skylab. “It really incapacitated us a lot,” Bean recalled in his NASA oral history. “The main effect we had was any time I did anything, we went off-attitude in the other axes.” For the entire crew, it was acutely disappointing. During training, their instructors had thrown hundreds of faults and failure scenarios and they had managed to overcome each one without so much as a blink of the eye or a bead of sweat on the brow. Now, said Bean, “we realised we were lucky we didn’t have some sort of explosion and blow that leaky quad thruster right off and really have a problem.”

The disorientating nature of the weightless environment, particularly in a large open volume like that of Skylab, offered many of the ingredients for “space sickness.” Photo Credit: NASA

The situation was complicated by the reality that, in 1973, devices to precisely measure a spacecraft’s closing range rate had not yet been invented. Owen Garriott, tasked with helping Bean to stick to the correct trajectory, had trained to use two range measurements from the on-board radar transponder at two different times, then had to divide the range difference by the time difference. By Garriott’s own admission it was imperfect, and it quickly became apparent that it was not slowing them down sufficiently to complete the rendezvous.

Still, Bean lauded Garriott as “a great ‘back-of-the-envelope’ guy,” capable of making accurate and rapid calculations and recommendations, but doubted his science pilot’s constant reminders that they were closing too fast and needed to apply more braking. The difference of opinion led Garriott, at one stage, to head down to the lower equipment bay, and that certainly got Bean’s attention. They were indeed closing too fast. Had it not been for Garriott’s admonitions, they would have closed too rapidly and sailed straight past Skylab, which would have necessitated a re-rendezvous, an unnecessary wasting of precious manoeuvring propellant and, in Bean’s eyes as the mission commander, would have been “real embarrassing.”

The astronauts’ first view of Skylab had come at a distance of more than 400 miles, and docking occurred a little under nine hours into the mission. From Lousma’s perspective, as he shot photograph after photograph during the rendezvous, it was both spectacular and unnerving; for the parasol erected by the station’s first crew looked decidedly flimsy. “It was flapping in the breeze … [of] the exhaust from our thrusters,” he told the NASA oral historian. “We thought we were going to blow it off, so we suspended the fly-around [inspection of Skylab] and went in and did the docking.”

JSC Director Chris Kraft looks grim during discussions in Mission Control at the height of the quad crisis. Photo Credit: NASA

Despite the good health of the station and—it seemed—the Apollo spacecraft, the first major obstacle quickly reared its head, when the astronauts fell victim to space sickness. The first affected was Lousma, who had begun experiencing the symptoms shortly after reaching orbit. He took a scopalomine-dextroamphetamine pill for anti-motion sickness and felt well enough to fulfil his duties during the rendezvous. However, very soon Bean and Garriott reported stomach “awareness” and were unable to move quickly around the interior of Skylab. At length, even with anti-motion-sickness medication, it was becoming difficult for the astronauts to prevent themselves from becoming ill.

Years later, Lousma vividly recalled that their arrival in the station exacerbated the problem. “We hadn’t spent a lot of time in … a volume [this large],” he recollected. “It was mostly in confined quarters, where you don’t have to move very much, but now we were climbing out of the command module and going through the tunnel into this big volume and we had all kinds of room to operate in and move around in.”

By the morning of 29 July, after a particularly unpleasant sleep, the breakfasts of Bean, Garriott, and Lousma were left partially eaten, and the astronauts found themselves behind with their timeline. A concerned Bean asked Mission Control for the opportunity to allow them to rest for a while and to move their first off-duty day forward from 3 August to 30 July; additionally, it was decided to postpone their first EVA by 24 hours. Originally, according to a detailed timeline published by NASA a few weeks earlier, no fewer than three EVAs were scheduled for the mission—on 31 July, 24 August, and 19 September—to install and retrieve film from the station’s Apollo Telescope Mount (ATM), but the first spacewalk was especially critical, since it would also involve the deployment of the Marshall Space Flight Center’s backup sunshade.

Bean’s crew had barely started their two-month mission and were already behind. Lousma would later admit to being perplexed at his unpleasant reaction to the space environment. He was a Marine, used to sickening aileron rolls and other stomach-churning aerial maneuvers and, along with his crewmates, had done a significant amount of training in rotating chairs on the ground, making various head movements to induce nausea and better “condition” themselves. It all appeared to have been for nothing. “Actually,” Lousma added, “on the ground, we were one of the most resistant crews to that kind of experience, but when we got in there, we were one of the least resistant!”

Original plans called for an EVA within days of arriving at Skylab to retrieve and replace film in the Apollo Telescope Mount (ATM). That spacewalk was repeatedly delayed as the crew suffered the effects of “space sickness.” Photo Credit: NASA

By 31 July, the men were feeling slightly better, and all were in finer spirits as August dawned—with Bean even demonstrating gymnastics to his television audience—although mission managers had by now elected to postpone the EVA a second time. Smaller meals were recommended in order to avoid nausea, but Bean would later argue that it was the timeline which was their real enemy. Everything they did took time—even finding new heads for their shavers—and as Houston sent more work to do, they found themselves bogged down with other tasks: troubleshooting Skylab’s balky dehumidifier, repairing the urine separator, and so on.

“Losing” things was a constant problem throughout the mission, since finding them again was quite unlike the chances of finding a lost item back on Earth. “We always seemed to look on hard surfaces,” said Garriott, “where we would normally have left it, but three-dimensional space is just too difficult to search visually.” After a while, they learned to start by checking the intake duct of the station’s air-circulation fans, where lint and debris—and, quite often, a few little items, pens, pencils, notes, and so on—would be rediscovered.

Aside from the time consumed by losing and having to find things, the sheer pace of that first week aboard Skylab was too hectic, and Bean was convinced that zooming around, unpacking equipment and supplies, and activating systems was aggravating their sickness. “We were not eating on time,” he explained, “we were not getting to bed on time, and we were not exercising.” All three, Bean felt, were absolutely crucial in ensuring a smooth adaptation from an Earthly lifestyle to the new environment, and he strongly advised the next crew to give them priority over the activation of the station. Space sickness was worrisome for other reasons, too. The space shuttle effort, approved by President Richard Nixon the previous year, envisaged seven-day missions in a spacecraft which offered a much larger volume than had previously been available. “Were we to lose three or four days out of each … flight because of motion sickness,” NASA Deputy Administrator George Low noted, “the entire shuttle effort would be in jeopardy.” It was not a minor issue.

Around six days after launch, Owen Garriott recalled they finally began to hit their stride. Then, another problem arose. And this time, it carried the potential to ruin their entire mission.

Source: https://www.americaspace.com/2013/07/28/a-sick-crew-and-a-sick-ship-the-trials-of-skylab-3-part-2/
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 07, 2019, 08:11
A Sick Crew and A Sick Ship: The Trials of Skylab 3 (Part 3)
By Ben Evans, on August 3rd, 2013 [AS]

Skylab, as seen by its second crew in 1973. America’s first space station celebrates its 40th anniversary this year. Photo Credit: NASA

The astronauts’ first week in orbit was particularly unpleasant, as all three men suffered the effects of debilitating “space sickness,” as described in last week’s history article. By the beginning of August, they had begun to hit their stride. Then, with unexpected abruptness, something happened which threatened to terminate their mission before it had really begun. Early on the morning of 2 August, Garriott was secured into a rotating chair aboard the station, checking his body mass, when Lousma called him over to a window. Neither man could believe his eyes: for there was a snowstorm, in full fury, outside!

Garriott assumed that it was an auroral display, for he knew that they were flying over New Zealand and the southern auroral region at the time. However, he was left open-mouthed as a flurry of snowflake-like particles—“a real blizzard,” he recalled—flooded past the window. “Since it doesn’t snow very much in space,” Garriott deadpanned to the NASA oral historian, “we realised there had to be another explanation and in this case it was obvious.” It was a fuel leak from one of their Apollo spacecraft’s quads of Reaction Control System (RCS) thrusters. Bean and Lousma quickly identified a problem with the Quad D set of thrusters, one of four quads spaced around the service module. Another set (Quad B) had already failed a few days earlier and had been shut down.

This image of Al Bean shaving illustrates the inherent difficulty of the microgravity environment, in which every item had to be checked and secured. Photo Credit: NASA

At first, a link was not made with the Quad B problem. Temperatures in Quad D were falling rapidly and the crew were first advised to activate its backup heaters. An hour later, a further drop in temperature and pressure was noticed, suggesting that a second leak, similar to the Quad B incident, had indeed occurred—a suspicion confirmed by visual observations from the crew.

“We could see [the quantity] going down on the meter,” Lousma recalled, “so we shut off all the valves and made sure everything was secure, just closed up all the plumbing and reported it to Mission Control.”

With two of the four RCS quads shut down, the situation turned ugly, for the quads were a critical component of their maneuvering capability and the astronauts were only six days into a planned eight-week mission! The rate of the oxidiser leakage was low—only 10 percent had been lost—but Mission Control and the crew were concerned, since there was no indication of how rapidly it would increase. They could use two, or even one, quads to get home, but it was not acceptable for re-entry without further investigation.

Of paramount importance was figuring out why the failure had occurred. Was it a systemic flaw? Would there be a continuous stream of failures? Or was it a random pair of unrelated incidents which gave the appearance of having a common cause? No one knew. Early supposition was that the batch of nitrogen tetroxide might have been contaminated, which placed a cloud of uncertainty over the other two thruster sets, Quads A and C. Moreover, if the leaks persisted, internal circuits aboard the service module might render the craft unusable. Later that morning, Bean spoke directly to Chris Kraft, director of the Johnson Space Center in Houston, Texas, imploring him to allow them to remain aboard Skylab to complete their mission, but he was advised that if the situation worsened a rescue mission with a modified command and service module might be attempted. “If we had another leak,” Lousma reflected, “we sure wouldn’t have enough to get home.”

Schematic of the seating arrangement for the Skylab-Rescue (SL-R) command module, utilising a field modification kit. Many of the spacecraft's stowage lockers would have been removed, to make room for three additional astronaut couches in the lower equipment bay. Image Credit: NASA

Acutely disappointed, the crew was now faced with the very real possibility of not only a curtailed mission … but maybe even the need for another crew to be hurriedly primed for launch to dock at Skylab’s second port and bring them home, abandoning their own craft. Rescue missions for Skylab had been extensively explored and planned for more than two years; indeed, rookie astronauts Vance Brand and Don Lind had undergone specific training to accomplish it. Both were experienced pilots and both were convinced that they could rescue Bean’s crew, if necessary. However, in August 1973 the dangers were evident: such a rescue mission had never been attempted, and if the thruster quad fault was a systemic flaw, it was possible that the rescue craft might be similarly affected. It would be a risky gamble … but one they were ready to take.

On 13 August, Time magazine reported the unsettling news from Skylab: that one of the service module’s four RCS thruster quads had sprung a leak shortly after launch and another quad had proven inoperable a few days later. Not only was Mission Control concerned that all four quads were of identical design, but their oxidiser—and the oxidiser for the big Service Propulsion System (SPS) engine—originated from the same batch. If that batch was contaminated, NASA could have a “generic” problem on its hands which might affect the whole spacecraft and prevent Bean, Garriott, and Lousma from returning home safely. In theory, Apollo could be controlled with just one quad or even using the thrusters on the command module itself, but the risk of further deterioration prompted the space agency to take steps to implement a rescue plan.

Pictured during the rendezvous procedure, this view clearly shows Skylab's multiple docking adapter, equipped with twin ports to support a visiting craft and a possible rescue craft. Photo Credit: NASA
Pictured during the rendezvous procedure, this view clearly shows Skylab’s multiple docking adapter, equipped with twin ports to support a visiting craft and a possible rescue craft. Photo Credit: NASA
Skylab’s multiple docking adapter carried two ports, which permitted such a rescue mission to visit. Yet the effort itself was audacious and called for a second Apollo to be outfitted with five seats: two for Brand and Lind and three others for Bean, Garriott, and Lousma. The stranded crew could then transfer from the station to the rescue vehicle and return to Earth. Assessments of the practicability of this plan were made in April 1971, and it was considered possible for NASA to launch the mission at any time between ten and 45 days after being given the go-ahead. It was by no means a simple “paper” exercise: by March 1972, NASA had committed itself to having a Skylab rescue capability, and Navy and Air Force search and rescue helicopters supported trials at sea later that same year.

As the pilots on the crew, Bean and Lousma had devoted extensive training time to the rescue scenario. “Al and I worked with Rockwell and the NASA engineers,” Lousma told the NASA oral historian, “in configuring a command module that had two flat couches underneath the three couches on top and that would handle five people. In the centre, between the two people on the very bottom floor—on the ‘bottom bunk,’ so to speak—there was enough room to put some of the experimental data and other kinds of things you’d want to bring back for data reduction.” The biggest concern was the potential “stroking” of the upper deck of couches. Normally, the standard three couches were designed to “stroke,” or have their supports compress like a shock absorber, in the event of a rough landing. If that happened to the returning rescue craft, the supports might compress … onto the astronaut in the couch below! However, since no couch had ever stroked during any of the previous dozen Apollo splashdowns, NASA considered the risk a minimal one.

Now, in the first half of August 1973, it seemed that a rescue mission might really happen.

Source: https://www.americaspace.com/2013/08/03/a-sick-crew-and-a-sick-ship-the-trials-of-skylab-3-part-3/
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 07, 2019, 08:17
A Sick Crew and A Sick Ship: The Trials of Skylab 3 (Part 4)
By Ben Evans, on August 4th, 2013 [AS]

Skylab 3 and astronauts Al Bean, Owen Garriott, and Jack Lousma returned safely to Earth on 25 September 1973, after 59 days in orbit. Yet for the first quarter of their mission, the exact duration of their flight remained open to question. Photo Credit: NASA

By the beginning of August, only days after launch, the crew had been hamstrung by debilitating “space sickness” and a mysterious leak from one of the four “quads” of maneuvering thrusters on their Apollo service module. The latter problem was of such severity that a rescue crew, consisting of fellow astronauts Vance Brand and Don Lind, was being readied for launch in a special five-seater craft to bring them home. Preparations at the Kennedy Space Center now shifted into high gear, with efforts to ready Pad 39B for its second Saturn IB launch in a few days. The booster to be used was the one already earmarked to transport the third Skylab crew into orbit in November.

The command and service module assigned to the Skylab-Rescue (SL-R) mission, together with its spacecraft adaptor, is pictured inside the Vehicle Assembly Building in February 1974, following the safe return of the third and final station crew. Photo Credit: NASA

On 3 August, the processing schedule was accelerated, with technicians and engineers working around the clock to prepare the vehicle for its potential new role. The Apollo command module (known as “Skylab-Rescue” or “SL-R”) would be stripped of stowage lockers in its lower equipment bay to accommodate the three couches and “ballasted” with lead to compensate for centre-of-gravity offsets. Upon receipt of the call, a field modification kit would be installed to house a five-man crew.

Launch of SL-R was scheduled for around 5 September, approximately three-quarters of the way through Bean, Garriott, and Lousma’s planned 59-day mission. On 10 August, less than a month ahead of this schedule, the SL-R Apollo was transferred to the Vehicle Assembly Building (VAB) for final checkout. By necessity, this work was abbreviated and it was expected that the spacecraft could be readied for installation onto the Saturn IB and rolled out to the pad in as little as three days. Flight readiness checks would then be accomplished by 24 August, propellant loading would commence on the 27th, and launch would occur a little more than a week later. The SL-R mission was expected to last no more than five days, ending with a splashdown in the Pacific on 10 September.

Brand and Lind—together with scientist-astronaut Bill Lenoir—had already trained together since January 1972 as backups for the second and third Skylab crews. Brand would have commanded SL-R, with Lind as pilot. “I did a lot of contingency work figuring out, for example, how you could complete a rendezvous if you lost your inertial navigation unit,” Brand told the NASA oral historian, “by gauging things, using charts, using the spacecraft guidance, navigation, and control equipment in ways that it was never, ever designed to be used. I thought I could almost fly the spacecraft without thinking at the time, because I had so much exposure to Apollo training.”

However, Brand had his doubts. He had become very familiar with the schedule of launch preparations for both the spacecraft and its Saturn IB booster and felt that the “long pole” in achieving their 5 September target was getting the vehicle ready on time. “I think we would have been lucky to be off 30 days after that,” he recalled, “but we were talking about that, aiming for that.”

When the trouble with Bean, Lousma, and Garriott’s spacecraft became clearer, Brand and Lind spent most of August 1973 “figuring out how to rendezvous with them, where we would dock, outfitting our command module so that it had … padding on the aft bulkhead where people could lie … [to] get five people in the spacecraft.” In addition to stroking the struts of the couches, the number of bodies inside the command module might have posed difficulties after splashdown; if the spacecraft entered a “Stable 2” orientation (with its apex in the water) it could prove disorientating. “Vance and I had gone through some training on this out in the Gulf [of Mexico] with a real command module,” Lind recounted in his NASA oral history. For the purposes of the five-man exercise, three other astronauts, including Bill Lenoir, had joined them.

“Now, if we get in Stable 2,” Lind told Lenoir, “remember you’re on top of the vehicle and so when you unstrap, make sure you have a hold of a stanchion someplace.”

Lenoir looked at his crewmate, incredulously, with an expression that read: “Lind, how dumb do you think I am?”

“Well,” Lind told the oral historian, “we got in Stable 2. The radio called for [Lenoir] to unstrap. It was hard to realise that you were now strapped [to] the ceiling, because it was bouncing around in the water. He released his seatbelt and, wham! Then he looked at me like ‘If you say one word, I’ll kill you!’”

Other considerations included which experiments the rescue mission could bring home, in view of the limited stowage volume aboard SL-R. Brand assigned Lind the job of “cargo master” to make these decisions, based on weight and center-of-gravity concerns. “I had to inventory all the possible decisions to maximise the scientific return with the limited capability we had to return all that data,” Lind recounted. According to contemporary NASA documents, in addition to the safe return of both crews to Earth, the main objectives were to bring back “selected” experiment data, to perform a diagnosis of the failure of the original Apollo craft, and to configure Skylab for a revisit. In terms of samples to be returned to Earth, the frozen urine specimens and dried feces were of primary interest from a medical standpoint. Film from the Earth resources instrumentation and Apollo Telescope Mount (ATM) were also critical.

Rollout of the Saturn IB for the Skylab-Rescue (SL-R) mission in August 1973. Pad 39B was originally designed for the large Saturn V, and the smaller Saturn IB required a “milk stool” to elevate it to the proper level to access the gantry’s utilities and umbilicals. Photo Credit: NASA

Aside from the rescue itself, the men worked a number of what Brand called “unorthodox” procedures, bypassing the service module and re-entering with only the command module’s thrusters. The mood was lightened when further investigation confirmed that none of the RCS oxidizer batches were contaminated and had not contributed to the leak. It also appeared that Quads A and C were unaffected and a subsequent investigation would attribute the failure to undetected loose fittings in oxidiser lines.

Throughout those heady days in August 1973, Brand and Lind developed a number of work-around procedures. One of these enabled Bean to achieve translational capability and complete the de-orbit burn with only the command module’s attitude thrusters. “We were so clever as the backup crew,” said Lind, “that we worked ourselves out of a flight! You really didn’t want to have to go rescue them.” Their workaround, together with the engineering expertise of others on the ground and of the crew in orbit, ensured that Bean’s crew could complete their flight. Rather than making a two-stage SPS burn for re-entry, it was decided that the men would perform a single burn and that if there were no more leaks, the rescue mission could be stood down.

Vance Brand (left) and Don Lind were assigned as the Skylab-Rescue (SL-R) crew. Photo Credit: NASA

In a strange way, it was disappointing, particularly for Lind, who had long desired a Skylab mission, but he knew that both Lousma and Bill Pogue were “depressingly healthy” and there would be essentially no chance that he would be called upon to take their place on a prime crew. Even the old backup crewman’s technique of straw dolls and long pins, it seemed, would have little effect. Flying the short SL-R mission was his last chance to see Skylab up close and in orbit.

As the situation began to improve, with the workarounds and the relief that the leaks did not represent a systemic flaw and the oxidiser batches were not contaminated, plans changed quickly. The decision to remove SL-R from consideration changed everything overnight. On 14 August, only days after the transfer of the spacecraft to the VAB, NASA announced that the Saturn IB was now being retasked for launch no earlier than 25 September; effectively, the agency was removing it from immediate duty as a rescue craft, since Bean, Garriott, and Lousma were already scheduled to land at around that time.

This decision ties in with Lousma’s assertion that “after about ten days or so” into the crisis, the crew was advised that they could stay aboard Skylab and continue their mission. The decision underlined a growing confidence that the crew would most likely be able to complete the planned 59-day flight. On that same day, 14 August, the Saturn—now reassigned to its original purpose of transporting the final Skylab crew—was rolled to Pad 39B to begin its own launch preparations. Nevertheless, upon the completion of hypergolic propellant loading aboard the booster on 10 September, the vehicle remained in a “Launch Minus Nine Days” stand-by status until Bean’s crew were safely back on Earth.

A few months later, in January 1974, the SL-R command and service module was transferred to the VAB, where it later saw service as a backup vehicle for the Apollo-Soyuz mission. After that, for many years, it resided in the Kennedy Space Center’s visitor area and, in 2007, was “commandeered” by NASA to aid studies of a similar rescue capability for the Orion spacecraft. It is interesting and appropriate that lessons from the past continue to be learned for the future and, indeed, the post-Columbia practice of having partial crews on stand-by for a rescue is by no means a new one: it had been pioneered, worked out, and perfected all those years ago.

For Brand and Lind, losing the chance to fly the rescue mission as a direct result of the thoroughness of their own work was a bittersweet experience. “You really feel not just a professional obligation, but also a personal obligation,” Lind remembered, “to the fellows on the crew that you know so well to do that job very well. We did the best job we could and were able to convince management that we had enough redundancy to bring the guys home with the quad problems.” For his part, Brand was philosophical. Commanding the world’s first-ever space rescue mission would have been an intensely rewarding achievement for the rest of his life.

Today—exactly four decades to the week since those momentous plans were being laid—we should take a moment to express relief: for although it would have been “interesting” to see Brand and Lind fly their mission, we should be thankful that they did not have to.

Source: https://www.americaspace.com/2013/08/04/a-sick-crew-and-a-sick-ship-the-trials-of-skylab-3-part-4/
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 09, 2019, 14:01
All the King's Horses: The Final Mission to Skylab (Part 1)
By Ben Evans, on November 23rd, 2013 [AS]

Boosted aloft atop a Saturn IB rocket, and utilizing a special “milk stool” to raise its umbilical connections to the proper levels on the Pad 39B gantry, the third and final Skylab crew takes flight on 16 November 1973. Photo Credit: NASA

Forty years ago, on 14 May 1973, the United States launched its first space station, Skylab (https://www.americaspace.com/2013/05/11/attitude-control-game-the-fateful-launch-of-skylab/), into orbit. The mission appeared to go badly from the outset, with aerodynamic forces during ascent ripping away a protective micrometeoroid shield and one electricity-generating solar array and leaving the second array clogged with debris. Eleven days later, after an enormous amount of preparation and replanning on the ground (https://www.americaspace.com/2013/05/12/get-me-up-there-the-plan-to-save-skylab/), the first crew was launched and triumphantly brought the station back to life (https://www.americaspace.com/2013/05/18/with-flying-colours-the-revival-of-skylab/). Returning to Earth after 28 days, they were followed by the science-heavy 59-day flight of the second crew in July-September, leaving only the third crew of Commander Gerry Carr, Science Pilot Ed Gibson, and Pilot Bill Pogue to begin a world-record-breaking 84-day mission in mid-November. Forty years ago this week, the flight of Carr, Gibson, and Pogue got underway … and despite its spectacular scientific success it will be forever remembered (somewhat unfairly) in the popular imagination for two things: a sick bag and the first “mutiny” in space.

Even before launch, the third crew lived in the shadow of the second crew, who had exceeded their mission goals and achieved a 150-percent science return. By the end of October 1973, NASA announced that Carr and his men would fly for at least 60 days, and perhaps as long as 84 days. One of the main worries was that the three men would fall victim to “space sickness”—properly termed “Space Adaptation Syndrome”—but with a U.S. Air Force Thunderbirds veteran like Bill Pogue as a member of the crew, surely the chances of him being one of the sufferers were infinitesimally small. For if anyone’s stomach could be turned upside down and inside out with multiple rolls and other churning maneuvers, with scarcely any ill-effects, Pogue was the man. It did not quite turn out that way.

The fortunes and misfortunes of Carr and Pogue in Project Apollo have been discussed many times. In the spring of 1970, both men were placed on what Pogue described in his NASA oral history as “a phantom backup crew” for Apollo 16, alongside veteran astronaut Fred Haise, with an anticipated (though not formally announced) future assignment to the Apollo 19 lunar landing mission (https://www.americaspace.com/2012/09/08/a-nation-of-quitters-nasas-lunar-withdrawal/). However, amid steadily tightening budget cuts, the final Apollo flights were canceled by NASA on 2 September 1970, and early the following year Carr and Pogue were teamed with scientist-astronaut Ed Gibson to fly the final Skylab mission. Since Pogue had trained as a command module pilot, it made sense for him to serve as pilot on the Skylab crew, for many of his former duties would translate from one role to the other. Carr, on the other hand, had originally trained as a lunar module pilot, and in Deke Slayton’s mind it made sense to offer him the commander’s seat. It made Carr only the fourth American to command a crew on his first flight in NASA’s history.

Gerry Carr leads his crew out of the astronaut quarters at the Kennedy Space Center in the hours before launch. Photo Credit: NASA

Slayton had another reason to give Carr this command. Personal recommendation went a long way, and Carr’s sterling work for Charles “Pete” Conrad on the Apollo 12 support crew (https://www.americaspace.com/2014/11/11/remembering-apollo-12-the-500-bet-and-the-lightning-strike-part-1/) had earned him deserved brownie points. Conrad was now “Sky King,” head of the Skylab branch of the astronaut corps, and had a big say in who should fly each mission. With all these factors in mind, it is not surprising that Carr received his command.

Integral to their training was an understanding of how the previous two crews had performed. “When the first crew came back after 28 days,” Carr reflected in his NASA oral history, “they were pretty wobbly, pretty weak. So the second crew and ours decided to bump up the exercise periods. Al Bean’s crew doubled their exercise period from a half hour to an hour a day. Turns out that didn’t appear to be enough, either, so we increased it again to an hour and a half.” One area that did cause serious concern was that Bean’s crew had hustled about their work too quickly, and it was felt that this course of action might not be wise in a mission lasting three months. “We began telling some of the managers that we didn’t think that rate of work was wise for an 84-day mission,” continued Carr, “because we weren’t sure that we were going to be able to sustain it. We thought that the workload should be slacked off some and there should be more rest. Everybody agreed to that and the experiments were slowed and spread out quite a bit.”

Unfortunately, more experiments were then added, “and we allowed ourselves to get trapped into this new situation.” Carr would find that he and his crew had over-committed themselves and, in orbit, after a few days, would be in real trouble.

In late October, NASA announced 10 November as the target launch date, with the first of up to five EVAs scheduled for a just week later to install the first set of film into the station’s Apollo Telescope Mount (ATM). Repairs of an antenna on the S-193 experiment would occupy a second excursion, whilst a third—planned for Christmas Day 1973—would include photography of Comet Kohoutek. A fourth EVA on 29 December would perform additional experiments and retrieve material samples from Skylab’s hull, and a final outing in mid to late January would collect the final sets of ATM film for return to Earth. Although NASA hoped to extend the duration of Carr, Gibson, and Pogue’s mission to 84 days, the agency cautioned that any extensions would be decided and implemented on a weekly basis.

In the meantime, the Apollo spacecraft and its Saturn IB rocket continued to be readied for flight. Standard pressurization and other checks in October had gone well, until, on 6 November, a management meeting at Cape Kennedy was interrupted by news that inspectors carrying out routine structural integrity checks had found hairline cracks in the aft attachments of the eight stabilizing fins at the base of the first stage. More than a dozen cracks were found in total. Most likely, the cause was related to age—the rocket stage itself had been delivered to the Cape more than seven years earlier and kept in storage for much of that time—but three months sitting on the launch pad, in the salty air of the Cape, was also a contributory factor. With the possibility that the compromised fins might be ripped away during ascent, NASA delayed the launch so that replacements could be installed. This was no easy task. Simply rigging the support platforms on the Pad 39B “milk stool” to remove the first fin took 35 hours. Nevertheless, by the early hours of 13 November the work was completed and launch rescheduled for the 16th.

Carr was particularly upset by the delay, since their original date on 10 November happened to be the official birthday of his parent service, the U.S. Marine Corps, founded in 1775. With the exception of John Glenn, who flew into orbit alone, Carr would become the first Marine ever to command a space crew. In order to commemorate both this anniversary and this milestone, the Commandant of the Marine Corps himself, General Robert Cushman, and several of his key staff were to visit the Cape and watch the launch.

The bitter disappointment over the delay was quickly replaced by frustration and, as the issue of the cracks was steadily resolved, by dark humour. “We started making some comments about calling the vehicle Old Humpty Dumpty,” Ed Gibson told the NASA oral historian. “Somehow, that got out in the press and, of course, those guys who were working around the clock, all day and all night, it didn’t sit too well with some of them.” Nothing was ever “said” … at least not until shortly before launch. “When we got about 20 minutes before launch,” Gibson continued, “we got this message from them: ‘Good Luck and God Speed from all the King’s Horses and all the King’s Men.’ It was a neat little comment!”

With liftoff scheduled for 90 seconds past 10 a.m. on the morning of 16 November, the astronauts ran through standard pre-launch medical checks, ate breakfast, and headed out to the pad. Once there, they were greeted by a scene of utter silence and stillness and an overwhelming sense that today was the real thing—the event for which each of them had devoted the best part of a decade preparing to complete. At the top of the elevator, the white room personnel, led by Guenter Wendt, set to work getting them settled into the spacecraft. Fellow astronaut Hank Hartsfield finished the final checks, crawled underneath the couches, and was gone. “After Hank exited the spacecraft … they closed the hatch and it was just the three of us in there,” Carr recalled, “and we began the preparations that we had done so many, many times on the simulator.”

Pad 39B was originally designed for the large Saturn V, and the smaller Saturn IB for the Skylab missions required a “milk stool” to elevate it to the proper level to access the gantry’s utilities and umbilicals. Photo Credit: NASA

The launch itself was picture-perfect and all three men would relate lucidly their memories of riding the Saturn IB. As propellants flooded into the combustion chambers of the eight H-1 engines, Bill Pogue likened the sound to someone having simultaneously flushed every toilet in the Astrodome. Seconds later, the behemoth left Earth, convincing Ed Gibson that the basement had just exploded. Pogue thought he stayed pretty cool and calm throughout the experience, but a later conversation with flight surgeon Fred Kelly assured him that his pulse had accelerated from 50 to 120 at liftoff. The vibrations in the command module’s cabin were intense throughout the climb; one of Pogue’s responsibilities was to follow the launch profile in his procedures book, and he quickly found that his hands (and the book) were shaking so much that he could hardly read it. The noise was so intense that they could hardly hear each other’s voices over the intercom between their suits.

Carr and Gibson agreed with Pogue that the first part of the ascent, in the lower atmosphere, was by far the most dynamic. “You get an awful lot of turbulence and a lot of shaking,” Gibson said. “I would equate it to being a fly glued to a paint shaker! There’s something massive there that you’re sitting in that’s really giving an extreme turbulence.” For his part, Carr likened the first part of the journey uphill to riding a train with square wheels. At the point of staging, when the first stage burned out and the single J-2 engine of the S-IVB second stage took over, the transition from four times their normal weight to around 1.5 G was acutely noticeable. Thereafter, flying the S-IVB for the remainder of the trip into orbit was a dream, and when its engine finally shut down, some 8.5 minutes after liftoff, all three men were astonished to observe that their supposedly “clean” craft was now filled with debris: dust, particles, paperclips, screws, and washers.

Their arrival in space was greeted with bewilderment. Looking “down” on Earth, Carr’s months spent studying terrestrial features and landmarks counted for nothing; he could see nothing that he recognised. Then, after about half an hour or so, he spotted the heel of Italy and it was this image which would remain with him, indelibly printed on his memory. “I’ve never forgotten that particular experience,” he said. For Gibson, the gradually receding coast of Florida was his first view of the glorious Home Planet. For Pogue, on the other hand, the euphemism known as “stomach awareness” would very soon take center stage.

Source: https://www.americaspace.com/2013/11/23/all-the-kings-horses-the-final-mission-to-skylab-part-1/
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 09, 2019, 14:02
All the King's Horses: The Final Mission to Skylab (Part 2)
By Ben Evans, on November 24th, 2013 [AS]

Skylab and its Apollo Telescope Mount (ATM) was a critical asset in observing Comet Kohoutek in the winter of 1973-74. Photo Credit: NASA

Forty years ago this week, in November 1973, NASA launched its third and final crew to the Skylab space station. As recounted in yesterday’s history article, Commander Gerry Carr, Science Pilot Ed Gibson, and Pilot Bill Pogue were tasked to complete a mission of at least 60 days, open-ended to 84 days, either of which would produce a new world endurance record. The enormous success of Skylab’s first and second crews—who repaired and revived the crippled station, then went on to accomplish 150 percent of their science goals—imbued NASA with a false sense of confidence that it could fully load the final crew with an excessive amount of work. As circumstances would transpire, the experience of Carr, Gibson, and Pogue would teach the agency to regard long-duration spaceflight in a quite different manner to its earlier, shorter-duration missions.

After docking with Skylab, late on 16 November, it was intended that the astronauts would remain aboard their Apollo command module overnight and enter the station early the following morning. The rationale was to aid their adaptation to weightlessness before entering the large, open, disorientating volume of Skylab. After two unsuccessful attempts, docking was duly accomplished eight hours into the mission, and the crew remained awake late into the night stowing equipment, when, all at once, Pogue felt sick. Years later, he explained to the NASA oral historian that the sensation took the form of a severe headache and nausea and that Carr’s suggestion to eat something did not help matters. In fact, a mouthful of stewed tomatoes (the only item left in Pogue’s evening meal) soon sent him scurrying for his sick bag.

One of the greatest ironies was that Pogue had actually taken scopalomine-dextroamphetamine anti-nausea medication before launch, whilst Carr had not … and yet the commander experienced no feelings of sickness whatsoever. Nor did Gibson. Under normal circumstances, Carr knew that he was not even allowed to drive after having taken “Scop-Dex,” and he most definitely did not want his ability to be compromised whilst in charge of a spacecraft. Of the three of them, Pogue, an ex-Thunderbird pilot, was considered the least likely to get sick. Years later, he would see it as evidence that none of the medical community had a real handle on what caused space sickness and, for the most part, the theories and the prescribed medications were inconclusive and of only limited usefulness. Now, of course, with the pressure on them as a crew not to get sick, they faced a real dilemma: what to tell the ground?

The disorientating nature of the weightless environment, particularly in a large open volume like that of Skylab, offered many of the ingredients for “space sickness.” Photo Credit: NASA

Skylab had drifted out of direct radio contact at this stage and it was Gibson who suggested simply disposing of the “evidence”—Pogue’s sick bag—in the station’s trash airlock and keeping quiet about the matter. In so doing, Carr agreed, they could avoid getting the medical community “all fuzzed” and hopefully get their mission off to a smooth start. To Gibson, the desire to avoid space sickness was a political one: the multi-billion-dollar shuttle had only recently been approved by Congress, and there were lingering worries that if astronauts could get sick and potentially incapacitated for several days, the whole raison d’etre behind having a reusable winged spacecraft might be compromised.

Things were not looking good. Carr and Gibson tried putting Pogue into the docking tunnel, hoping that air from a cabin fan might make him feel better, but to little effect. Before retiring for the night, Carr read his status report to the ground, admitting to Pogue’s nausea and highlighting that he had not eaten all of one of his meals. Unluckily, one of Pogue’s responsibilities was the spacecraft’s communications system … and, as specified in the checklist, he had left the switch “on” to the equipment which was recording their in-cabin conversations. Whilst the crew slept that night, Mission Control downloaded the tape and heard all of their discussion about concealing the evidence!

Early the next day, 17 November, Pogue felt better, but took things slowly as he and his comrades ate breakfast. By mid-morning, they were inside Skylab. Carr switched on the lights and the men set to work on their respective duties: setting up communications links, starting the environmental control system, and reactivating the station. In the meantime, back in Houston, the tapes from the previous evening were being transcribed and their startling contents led to a medical conference to be convened that afternoon. Later, Chief Astronaut Al Shepard came onto the capcom’s console to address Carr directly.

“I just wanted to tell you,” he said, “that on the matter of your status reports, we think you made a fairly serious error in judgement here in the report of your condition.”

Carr accepted the rebuke. “Okay, Al, I admit it was a dumb decision.”

Ed Gibson, pictured at the controls of Skylab’s Apollo Telescope Mount (ATM). Photo Credit: NASA

Shepard was not to be put off. If Pogue’s sick bag had been disposed of in the station’s trash airlock, it could screw up many of the medical experiments. Shepard pressed Carr to assure him that they had not gotten rid of the bag and that its contents would be weighed, as per the crew’s training, for mineral balance studies.

The incident, whilst relatively minor, underlined in some managers’ minds a fear that Carr’s crew were unwilling to engage in frank and open communications with Mission Control. Flight Director Neil Hutchinson did not doubt the crew’s integrity, but made certain that any further problems would require flight controllers to take immediate steps to set matters right. The situation would grow markedly worse over the coming days. Even three decades later, Bill Pogue would recall that he got on perfectly well with both Carr and Gibson, but felt it would have been nice to have had an experienced crewman aboard. They were the first all-rookie U.S. crew since Gemini VIII in March 1966. In hindsight, Gibson acquiesced, they could and should have handled it differently. “We should’ve just said: ‘Hey, guys, your pills didn’t work. They’re wafting across the command module now, along with Bill’s tomatoes!’ That’s probably the most regrettable thing I have about that whole flight … that we were not smart enough to handle it properly, because it caused everybody a lot of problems.”

With Pogue recovered, the crew realized that they were behind schedule and needed to work hard in order to catch up. Aside from adaptation to their new environment, the crew’s first week in space included a spacewalk by Pogue and Gibson on 22 November—Thanksgiving Day—to reload film into the Apollo Telescope Mount (ATM) and check out an inoperable antenna on an external radiometer/scatterometer and altimeter, known by the experiment code number of “S-193,” which was part of the Earth resources payload. The day concluded in fine style, with an ample Thanksgiving dinner. Carr selected prime ribs, Gibson went with turkey, and Pogue chose chicken. It was very good food, but they did note a tendency of blandness. Condiments helped a little, although they had to be used sparingly, lest they interfere with the medical experiments.

Whether afflicted by sickness or not, the three men also needed time to get themselves adapted to their strange new environment. During the first few days, Carr elected to swap roles with Pogue, “because my job was more sedentary than his.” Gradually, this enthusiasm became wearing, for the performance of Bean, Garriott, and Lousma had encouraged mission planners to pile more work onto Carr’s team. If they missed a step or made a mistake with a task, the timeline was so densely packed for all three men that they would end up racing against the clock, fighting a losing battle to keep up. “It was hard on morale,” Carr recalled. “We were rushed and not able to get things done and experiments completed.” The low morale was accompanied by an acute feeling that they were letting down the principal investigators; they pictured the scientists on the ground grinding their teeth as the three astronauts kept reporting that they were unable to complete all tasks on time because they were rushing around too much, making mistakes.

This image of Comet Kohoutek was acquired by a member of the final Skylab crew, 40 years ago. Photo Credit: NASA

Circumstances were not aided by the rather unpleasant attitude taken toward the astronauts by several of the scientists, some of whom regarded the crew as little more than a trio of semi-trained chimps. Early in the mission, Pogue was assigned to photograph a barium cloud, exploded by a Black Brant IV rocket launch from Fairbanks, Alaska. The objective of the NASA-funded study was that the barium vapor would be injected into Earth’s magnetosphere and, after ionization by solar ultraviolet radiation, would illuminate geomagnetic field lines and make them visible to sensitive equipment on the ground. However, after struggling to find each piece of equipment needed for the camera, Pogue positioned everything in the correct angle, checked his watch to ensure that all was ready … and saw nothing. “Where’s the barium cloud?” he recalled later. “I missed it. I don’t know why none of the numbers worked, but in any event I missed the cloud.”

Despite not understanding the problems that Carr’s crew faced in space, particularly during initial adaptation, those first few days of the mission seemed to reinforce this notion. “Then we discovered that we had been scheduled at nearly the same rate that the second crew had achieved at the end of their flight,” Carr continued. “That explained why we were having so much trouble keeping up. But by the time that was finally recognized, we had achieved a skill level that was adequate to get the work done.” They ate dinner together, partly for the social contact and partly to cement their cohesiveness as a crew, but found themselves hurrying off to work on experiments until well into the evening. By bedtime, none of them felt ready to sleep, because there were tools and pieces of equipment to put away or set up for the following morning. Their minds were moving too fast to rest, which impaired their ability to sleep and caused their productivity to suffer. Planners on the ground began to reschedule their exercise sessions to enable them to catch up on the experiments. There was nothing wrong with that, it seemed … until it became clear that at least one exercise session was scheduled right after dinner! “That’s no time to be exercising,” observed Carr afterward, “particularly up there, where you couldn’t belch, because with your food floating around inside you, you were liable to get it back with your belch.”

The final Skylab crew was tasked with its first EVA only a week after arriving in space. Photo Credit: NASA

Not surprisingly, as time wore on the crew became quite testy with Mission Control. Carr had requested before launch that their first day off, scheduled for 19 November, should be cancelled, but Flight Director Neil Hutchinson felt that they would benefit from the free time and two opportunities were made available in the first few days. On the evening of their second free day, Carr told mission controllers that the week had been “frantic” and that they were struggling to keep to the timeline.

Words of wisdom from Ed Gibson’s high school track coach summed up the crew’s feeling: If you want to win the quarter-mile race, sprint the first hundred yards, then just gradually increase your pace. Aboard Skylab, they were moving so fast, and so constantly, that it was impossible to avoid making mistakes. On more than one occasion, Gibson recalled floating through the multiple docking adaptor, muttering creative profanities, little realizing that the voice recording link to the ground was open. “The situation,” he explained, “was compounded a bit because people had not yet fully come to grips with the fact that Skylab was a different animal than all the relatively short missions to date.” For ascent and re-entry, fine, it was necessary to have their timelines spelled out in second-by-second detail, or at least in blocks of a few minutes, but on an extended mission of three months, such micromanagement was neither suitable nor appropriate.

Nor was there an option to simply have a heart-to-heart with the ground and thrash things out, because all communications had to be open for the whole world to hear, including the press. At one stage, the astronauts decided to make better use of their time by having one of them listening for radio traffic at a time, thereby allowing the others to switch off the distraction of their radios and get on with their work. This worked well for a time … until, during one particular orbit, they forgot and all three of them left their radios switched off for an entire pass. “That caused a lot of concern on the ground,” Carr said, “and, of course, the press just thought that was wonderful.” In their sensationalist minds, the astronauts were on strike, on the brink of mutiny, turning their radios off deliberately. It was an unfair accusation which led to a stigma that would hang over Carr’s crew for decades.

Source: https://www.americaspace.com/2013/11/24/all-the-kings-horses-the-final-mission-to-skylab-part-2/
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 09, 2019, 14:02
All the King's Horses: The Final Mission to Skylab (Part 3)
By Ben Evans, on November 30th, 2013 [AS]

The crew of America’s final Skylab mission: Gerry Carr, Ed Gibson, and Bill Pogue. They were the first humans to spend New Year in space in 1973-74. Photo Credit: NASA

Already, space sickness had stricken Pogue within hours of arriving at Skylab, and within a few weeks the excessive workload began to take its toll on them all. The three men took a stoical outlook, trying to push on with their work and hope that circumstances would improve. They did not. It was time for Carr to make a stand. Having made it known prior to launch that his crew intended to take the activation of the workshop at a slow pace and ease their adaptation to the strange microgravity environment, on 6 December—two weeks into their mission—he spent several minutes explaining to Mission Control that the schedule was too full. His crew would not be expected to work for 16 hours a day, every day, for 84 days, on Earth, so it was unfair to expect it of them in space. There the issue rested for a time and little more was said during the last couple of weeks of the month.

Christmas—the second one to be celebrated by Americans in space, after Apollo 8’s message from lunar orbit in 1968 (https://www.americaspace.com/2014/12/21/there-is-a-santa-claus-the-voyage-of-apollo-8-part-2/)—helped to distract the men from their workload, together with the anticipated arrival of Comet Kohoutek. Carr’s crew built a crude yuletide tree out of packing material from food containers and decorated it with makeshift ornaments. They even crafted a small, long-tailed star from silver foil and put it in pride of place at the top of the tree, in honour of their cometary visitor. Systematic studies of Kohoutek from Skylab had begun on 23 November, when Pogue used a photometric camera to record its intrinsic brightness, followed by analyses of the composition of its coma and tail a few days later. By the weekend before Christmas, more than a dozen such observations had been completed. Another EVA, conducted by Carr and Pogue, took place on Christmas Day, one of whose objectives was photography of Kohoutek. “Bill and I were out for seven hours,” Carr recalled. “I was amazed when I got back in, because I expected that I’d have to go to the bathroom something fierce, but I didn’t. Apparently, I’d gotten rid of a lot of fluids in the form of sweat through my pores. When I got back in, I was really sweaty, but I really didn’t have to urinate. I was just amazed that, after seven hours, I wasn’t pretty interested in streaking to the urinal!”

Photography of Kohoutek was one of Bill Pogue’s tasks, and in his NASA oral history interview he remembered floating in the station airlock, surrounded by cameras, two large film magazines for the station’s Apollo Telescope Mount (ATM), and tools which Carr would use to routinely service the solar observatory. “Gerry went hand-over-hand to the end of the solar observatory,” Pogue related, “while I got the replacement film magazines ready. I operated an extendable boom to transfer the first film canister to Gerry; he removed it and loaded the exposed canister to the boom; I retracted the boom while Gerry loaded the fresh canister to replace the one he had just removed and when he gave me the okay, I sent the second canister out. We repeated the procedure and were finished in record time.” Next came the photography of the comet. Pogue carefully set up his camera, mounting it onto a strut and positioning it such that one of Skylab’s ATM arrays barely blocked the Sun. He could not physically see the comet, but Mission Control had earlier sent him a diagram on the teleprinter. “The instructions were clear and it was a fairly easy job,” he recalled. “I turned on the camera and I was finished.”

Also finished was Pogue’s experience of spacewalking, for this second excursion would be his last; the next two EVAs would both be undertaken by Carr and Gibson. His adventure ended at the solar “end” of the ATM, offering him a stunning and unobstructed view of Earth; it felt like Pogue was doing a swan-like dive through space. His fun was arrested by a sudden call from Gibson. One of the station’s three gyroscopes had failed during the 22 November EVA and now, as Pogue lingered close to the ATM, he was actually causing a second one to throw a fit. “Our suits were fed by oxygen from inside Skylab,” he explained, “and there was no recycling of the air. It automatically fed in near the back of my head, flowed down across my face and then escaped out the front of the suit near my waist. The outward airflow had acted like a small thruster, like letting the air out of a balloon. Although the force from the escaping air was small, my position at the Sun ‘end’ of the ATM magnified the thrusting effect because I was about 30 feet from the centerline of Skylab. In other words, this lever arm was giving the force of the escaping air a lot of leverage. The airflow from my suit was rotating a one-hundred-ton space station!”

The experience, though, was more than worth it, particularly when the men returned inside the airlock and were advised that, with a duration of six hours and 54 minutes, they had set a new world record for the longest EVA to date. Yet the relentless march of the timeline continued to conspire against them. Pogue complained on 12 December that the tight schedule had lost him the chance to complete a series of assigned photographs, because he had to set up the required equipment in a hurry, and on the 20th Gibson recorded that managing the crew’s time with teleprinter messages which dictated their day on a minute-by-minute basis was “no way to do business.” He even described the first five weeks in space as “nothing but a 33-day fire drill.”

On 28 December, after submitting his status report for the day, Carr told Capcom Dick Truly that he was preparing a special message for Mission Control to be sent later that evening before retiring to sleep. He wanted a discussion about the concerns the following day. If it took a couple of hours, everything else would have to wait. Any hope that the conversation could be aired on a private loop was gone and the press jumped hungrily on the matter. “We started talking … as we came up over Goldstone [tracking station in California],” Carr explained. “We had the whole U.S. pass, essentially, for me to tell them all the things that were bothering us. We need more time to rest. We need a schedule that’s not quite so packed. We don’t want to exercise after a meal. We need to get the pace of things under control.” Carr concluded his remarks by asking for Mission Control’s response during the next communications pass. Throughout this 20-minute period of recess, he conferred with Gibson and Pogue to put together a summation of their needs. “During the next pass, they bent our ear with all of the things that we were doing, including our rigidity that made it difficult for them to have the flexibility to schedule us how they needed to.”

All told, the conversation ran for almost an hour and covered a multitude of issues. Dick Truly assured them that everyone was happy with their performance. With Deke Slayton and Johnson Space Center (JSC) Director Chris Kraft in attendance, Truly felt the need to provide an assurance. “Gerry, let me say one thing,” he said. “Dr. Kraft and Deke have been here and listened … and they’re very happy with the way you’re doing business … and they think we’ve made about a million dollars tonight.”

It was not vain praise. Mission managers had already lauded the crew’s performance after a month in orbit, and Skylab Program Manager Bill Schneider had told the press on 13 December that Carr’s team had completed 84 hours of solar observations, 12 Earth-resources passes, 80 photographic and visual surveys, all of their assigned medical tasks, and three major repair jobs. Unless something unforeseen transpired, Schneider told the gathered journalists, he was optimistic of a mission lasting at least 60 days, “open-ended to 84.” Years later, Ed Gibson would laud Gerry Carr for making a stand on the matter of the schedule, although, tellingly, he noted that Mission Control was by no means blameless, even describing their continuous demands and requests as “obnoxious.”

The makeshift Christmas tree built by Carr, Gibson, and Pogue from old food containers and packaging also included a long-tailed star at its tip: Comet Kohoutek. Photo Credit: NASA

Next morning, 30 December, Houston came back with a list of recommendations. One was that the crew’s menial, routine chores would be put on a “shopping list” to be completed when time permitted during the course of the day. Moreover, the men would no longer be hassled during meal times and they would be given no major assignments after dinner in the evening. The experiments, however, which needed to be “hard-scheduled” to a particular time slot, would need to remain as they were. Fine, Carr replied, aware that this opening-up of the schedule had already taken much of the pressure off their shoulders. In fact, this schedule even allowed them to conjure some experiments suitable for television audiences on Earth. Several of these, including demonstrations of the behaviour of water in weightlessness, are still used today as part of classroom science experiments. From Mission Control’s perspective, Flight Director Neil Hutchinson admitted that there were indeed several serious scheduling and performance problems in the flight. Indeed, Harvard Business School would later publish a case study about Carr’s “strike” in space, detailing unrealistic expectations and miscommunication as part of a flawed management process.

To this day, perhaps unfairly, the achievements of Carr’s crew are overwhelmed in the popular press by the unfortunate label that they were the first to stage a “mutiny” in space. In a sense, the over-performance of Al Bean’s team had contributed to the stress under which Carr, Gibson, and Pogue had worked for the first six weeks of their own mission. Years later, Bean would accept that NASA had failed to properly switch gears after his flight and appreciate that Carr and his men would be aloft for a much longer period of time. More detrimental was that Mission Control started Carr’s crew at the same point that Bean’s crew had reached at the end of their mission. At one stage, Chris Kraft called Bean and Pete Conrad to his office to discuss the issue. “Mission Control plans to lighten up on these guys,” Bean implored Kraft, “but they don’t ever do it. They have to lighten up and let these guys catch their breath!” Also aware of the problem was unflown astronaut Bob Crippen, who had led the ground-based Skylab Medical Experiments Altitude Test (SMEAT) a year earlier; he felt that Charles “Pete” Conrad’s crew had spent much of its time repairing Skylab, with relatively little time on the experiments, and Bean’s men had the advantage of a slow start, ramping up into a more aggressive final few weeks, when they were properly adapted to the new environment. Carr, Gibson, and Pogue were being literally burned out from the start. It was not a good philosophy for executing a long-duration space mission.

As one of the team of capcoms for this flight, Crippen knew that the events of 28 December by no means reflected any kind of rebellion on Carr’s part; rather, they offered Mission Control a wake-up call to understand the problems that the astronauts faced. After the heart-to-heart, everything smoothed out and the final six weeks ran much more smoothly and pleasantly. The drive to achieve the highest possible performance from the crew was a hard-won lesson, Ed Gibson recounted, but it was a lesson which would have untold ramifications in the planning of future long-term missions, including those aboard today’s International Space Station.

Source: https://www.americaspace.com/2013/11/30/all-the-kings-horses-the-final-mission-to-skylab-part-3/
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 09, 2019, 14:02
All the King's Horses: The Final Mission to Skylab (Part 4)
By Ben Evans, on December 1st, 2013 [AS]

Spectacular view of Skylab, as seen from the departing crew of Gerry Carr, Ed Gibson, and Bill Pogue on 8 February 1974. This would be the last occasion that Skylab was ever seen, up close, by human eyes. Photo Credit: NASA

As recounted in yesterday’s article, an initial bout of space sickness, suffered by Pogue shortly after arrival in orbit, and several weeks of intensive, minute-by-minute scheduled activities—which Gibson later described as “nothing but a 33-day fire drill”—gave way to a heart-to-heart between Carr and Mission Control, in which the overloaded timeline was relaxed a little. Although it unfairly tarnished the crew as the first in history to stage a “space mutiny,” the stand actually made the remaining few weeks of the 84-day mission considerably more pleasant and productive for the astronauts.

With terse exchanges going on between space and the ground, it might at first glance seem surprising that another EVA by Carr and Gibson was undertaken on 29 December, acquiring more photography of Comet Kohoutek and collecting samples from the micrometeoroid cover of Skylab’s airlock. Central to the photography effort was the far ultraviolet camera, built by the Naval Research Laboratory. Like many disappointed observers back on Earth, the astronauts could hardly describe the long-haired messenger as brilliantly spectacular, but Carr was impressed, nonetheless. “It was so faint,” he told the NASA oral historian, “that we really had to work to find it. Once we did find it, we observed a gorgeous thing: small, faint, but gorgeous.” Still, although he and Gibson shot as much film as they could during their three and a half hours outside, they privately doubted that it was sensitive enough to record sufficiently good data. Over the next few days, from inside the workshop, the best results came from the ATM’s coronagraph … and, interestingly, from a series of pencil sketches by Gibson himself, today enshrined within the hallowed precincts of the Smithsonian.

With the dawn of the New Year, 1974, much of the comet-hunting on the ground had come to an end and there was much disappointment that Kohoutek had not lived up to its media-hyped billing. Journalists started calling it the “Flop of the Century,” ignoring the scientific yield and focusing only on its brightness as a marker of significance, but in reality the fault lay fairly and squarely upon their shoulders, for it was the media which treated Kohoutek as a sure thing, a dead cert, right from the outset. In March 1974, Sky & Telescope glumly told its readers that, whilst professional astronomers were jubilant with their observations, “the general public wondered what had happened to the spectacle promised by the news media.”

If the media were disheartened at the start of 1974, the crew aboard Skylab considered the last six weeks of their mission to be much more satisfying than the first six. Work aboard the orbiting laboratory was pleasurable, at last, and fleeting moments of joy and humour came from regular contact with loved ones back on Earth. On one occasion, Gibson described for his wife and their children the beauty of watching fires along the coastline of Africa. He hoped that they would be hanging excitedly onto his every word … until Julie, his youngest daughter, asked her mother if she could go outside and play! On another occasion, Pogue was disturbed by a message from his wife, alerting him that she had received a letter, providing information that her husband’s life insurance policy was about to expire. Pogue was particularly irritated, since he had requested the possibility of making a three-month pre-payment into his policy, before launch, to cover the time that he would be away … and was told that pre-payments were not possible, but assured that the policy would remain effective throughout his mission.

In the days preceding their launch, Carr’s crew was tentatively scheduled to return home in the early part of January 1974, after around 56-59 days, but the assumption was that extensions would be considered on a weekly basis, depending upon consumables and the good health of the astronauts. These extensions came thick and fast through the month of January. Three days before they were due to break the 59-day record set by Al Bean’s team, NASA officially extended them to at least 63 days, with Skylab Program Manager Bill Schneider praising their “good spirits,” their “excellent physical condition,” and the “good shape” of Skylab itself.

Astronauts Vance Brand, Bill Lenoir, and Don Lind served as backups for both the second and third Skylab crews and might have flown the 21-day fourth mission, had it been approved. Photo Credit: NASA

It was a dramatic change and remarkable turnaround from the exhausted trio of spacefarers who had struggled to keep up with the timeline a few weeks earlier. Another extension pushed their mission to 70 days, with splashdown rescheduled for no earlier than 24 January, then further into the first week of February, and finally settling on the 8th. “The last six weeks of the flight were very pleasant for me for two reasons,” Bill Pogue remembered in his NASA oral history. “One, we’d achieved the skill level sufficient to do the job quickly and accurately, and second, I no longer suffered from the head congestion that had plagued me for about the first six weeks.” As they neared the 12-week limit, Pogue even hinted that NASA Administrator Jim Fletcher wanted them to spend an additional 10 days aloft, but mentally the crew were ready to come home and, besides, the consumables aboard the workshop were almost exhausted.

A potential fourth Skylab visit, lasting three weeks and possibly crewed by Vance Brand, Bill Lenoir, and Don Lind, was unlikely to ever take place. It had been considered as an option early in the spring of 1973, but, according to spaceflight historian Dave Shayler in his book Skylab: America’s Space Station, “proceeded no further than coffee-table discussions.” Had it flown, one of its primary functions would have been to mothball the workshop and perhaps conduct a few more experiments. However, the extension of Carr’s mission by a month past its original 56-day mandate sufficiently maximized the scientific return from Skylab and eliminated the need to launch a costly additional flight. On 3 February 1974, Carr and Gibson performed the final EVA from the station, retrieving the last of the film from the Apollo Telescope Mount (ATM) and gathering other material samples for return to Earth and subsequent analysis.

Five days later, the time was upon them to leave. No more crews were expected to occupy the station, although there was a faint hope that a space shuttle might someday visit, perhaps to re-boost it into a higher orbit for possible future use. For that eventuality, Carr, Gibson, and Pogue left a sort of time capsule—a variety of material samples, held inside the station, but kept in vacuum, since Skylab was depressurized shortly after their departure—which a subsequent crew might collect. However, there was little time to ponder. Frozen urine samples had to be stored aboard the command module, as did the material science samples and the film cassettes from the ATM and other equipment. The men went about their tasks with enthusiasm, finally undocking and performing a flyaround inspection of their old home, then firing the service module’s engine to depart for the last time.

Whilst Ed Gibson elected not to grow a beard during his mission, his two crewmates, Bill Pogue (left) and Gerry Carr opted for the “Hairy Monster” look. Photo Credit: NASA

With Skylab now gone from their immediate lives, the crew duly jettisoned the service module … and ran straight into a problem. “I looked over at Gerry as he was moving the hand controller,” explained Pogue, “to get the right entry attitude, which we absolutely had to be at for re-entry to avoid landing in the wrong location or being cremated before our time … and nothing was happening.” He advised Carr to “go direct”—to go to the hard stops on the hand controller, bypassing all the black boxes and putting the “juice” directly to the solenoids controlling propellants in the reaction control thrusters. Fortunately, directness worked and re-entry proceeded without further difficulty. It later became clear that in the gloom of orbital darkness, Carr had mistakenly pulled the circuit breakers for the command module, instead of the service module. “It was dark,” Pogue concluded, “and he just pulled the wrong ones. But it turned out fine.”

Descending through the steadily thickening atmosphere was truly spectacular. Ed Gibson likened it to travelling through a purple neon tube of gradually increasing brightness and intensity, and as the forces of extreme deceleration increased, a white-hot sheet of flame enveloped them. They were no longer in a neon tube; they were in a blast furnace. From the center seat, Gibson could see the command module’s thrusters pulsing as the computer actively guided them toward their splashdown point, a little under 186 miles (300 km) southeast of San Diego. Less than 3 miles (5 km) away, steaming toward them, was the helicopter carrier U.S.S. New Orleans, their prime recovery ship.

In the beautifully calm waters of the Pacific, the command module of the final Skylab crew bobs gently after 84 days in space. Photo Credit: Joachim Becker/SpaceFacts.de

Splashdown, when it finally came, was into a thankfully calm sea, with virtually no wind, although the command module quickly assumed the inverted “Stable 2” position. Within moments, though, the flotation bags around the spacecraft’s apex inflated and bobbed it over into the Stable 1 configuration required for the recovery operation. Helicopters hovered nearby and frogmen were soon in attendance. Dawn had barely broken in the Pacific and the final Skylab crew were safely home. They had left Earth as NASA’s first team of rookie spacefarers in almost a decade … and had returned as world record-holders, having jointly secured an impressive mission of 84 days since their November liftoff. None of them felt seasick, although the sensation of weight was strong; Gibson could feel his head on his shoulders and it took great effort simply to move his arms, but all three men could be thankful and deeply satisfied that their long mission had ended in fine fashion.

As circumstances transpired, no shuttle visit to Skylab ever took place, although plans were afoot to conduct one. Delays in the development of the reusable spacecraft, and an unexpectedly fierce bout of solar activity, conspired to bring Skylab back into the atmosphere in a largely uncontrolled re-entry in July 1979. And thus ended America’s first foray into the space station business. Skylab had proven a tremendous success and, in some minds, a wasted opportunity, for its potential applications alongside the shuttle in the 1980s and as the basis for an “earlier” International Space Station could have been profound.

Source: https://www.americaspace.com/2013/12/01/all-the-kings-horses-the-final-mission-to-skylab-part-4/
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 09, 2019, 14:02
Skylab's Long-Haired Messenger: The Visitation of Comet Kohoutek
By Ben Evans, on August 10th, 2013 [AS]

Skylab and its Apollo Telescope Mount (ATM)—seen here with its “windmill” of solar arrays—was a critical asset in observing Comet Kohoutek in the winter of 1973-74. Photo Credit: NASA

Forty years ago, nine men occupied America’s first space station, high above the Earth. Much of the history of Skylab is clouded by its early troubles following launch—one of its solar arrays was torn off, another left jammed by debris—and the actions of its heroic astronaut crews to bring it back from the brink of outright failure and transform it into a remarkable success (https://www.americaspace.com/2013/05/18/with-flying-colours-the-revival-of-skylab/) cannot be underestimated. Yet Skylab was always intended as a quantum leap in the U.S. human spaceflight arena, with dozens of scientific experiments planned. One of the most visible, at least in the winter of 1973-74, was the arrival of a long-haired messenger, a few tens of millions of miles from Earth: Comet Kohoutek.

Comets have long been thought to carry ill-tidings and, certainly, for the first year of Skylab’s life, good and bad luck were but different faces of the same coin. Nearly a thousand years ago, a comet convinced King Harold’s men that cruel fortune awaited them on the battlefield of Hastings, and to the ancients they foretold imminent catastrophe: a plague or a flood, perhaps, or the impending death of a nobleman or king. To the biblical Book of Revelation and the Jewish Book of Enoch, such “falling stars” were believed to represent heavenly visitations, and in 7 BC King Herod is said to have been warned that the apparition of a “hairy star” over Judea would herald the birth of a boy whose achievements would outshine his own.

Indeed, until the 16th century, the mainstay of scientific opinion about the nature of comets rested with the Greek philosopher Aristotle, who believed that they could not possibly belong to the “perfect” celestial realm and posited that they were a phenomenon of the upper atmosphere, from which hot, dry exhalations gathered and burst into flame. Then, in 1577, the Danish astronomer Tycho Brahe used measurements of a comet taken from several geographical locations, including some by himself, to determine that it must have been at least four times more distant from Earth than the Moon. In Brahe’s mind, comets could not be elements of the upper atmosphere, but must represent something from beyond.

Billed in some quarters as the “Comet of the Century,” Kohoutek came to be viewed by many as a spectacular dud. Photo Credit: NASA

Since the beginning of the Space Age, our understanding of these long-haired messengers has sharpened: we now know them to possess irregularly-shaped nuclei of rock and water-ice and a multitude of other volatiles—prompting the nickname of “dirty snowballs”—and as they approach the inner Solar System, these volatiles quickly vaporise and stream away, carrying dust particles with them. These streams create a vast “atmosphere” around the comet (its “coma”), and the force exerted by the Sun’s radiation pressure and solar wind cause immense “tails” to form, sometimes many millions of miles long.

Our knowledge of their appearance, their composition, and their evolution has multiplied, thanks to our extraterrestrial emissaries: from Giotto’s impressive photographs of the nucleus of Halley’s Comet, with its “jets” of dust, in the winter of 1985-86, to Deep Space 1’s astonishing shots of the hot, dry Comet Borrelly 1 in September 2001, to Stardust’s collection of crystalline, “fire-born” material from Comet Wild 2 in January 2004, to Deep Impact’s spectacular effort to blast a man-made crater into Comet Tempel 1 in the summer of 2005. Further flights of exploration are also planned. A second voyage of Stardust revisited Tempel 1 in February 2011 to analyse the after-effects of that collision and to test the hypothesis that much of the ice in a comet is stored in subsurface “reservoirs.” Europe’s Rosetta spacecraft will land its instrumented Philae probe onto Comet Churyumov-Gerasimenko in November 2014. Once there, Philae will use harpoons and drills to physically anchor itself, for the first time, onto the surface of a comet.

As for Comet Kohoutek, it was first spotted on 7 March 1973, by Czech astronomer Luboš Kohoutek, a professor at the Hamburg-Bergedorf Observatory in West Germany, whilst he was undertaking observations of minor planets. At the time, it was little more than a diffuse point of light, moving slowly north-westward in the constellation of Hydra, but its distance from the Sun—some 5 Astronomical Units (AU) or around 460 million miles—quickly whetted astronomers’ appetites that it would be a particularly bright comet. Calculations by Brian Marsden of the Smithsonian Astrophysical Observatory in Cambridge, Mass., added that it would reach a perihelion of just 0.14 AU and would subsequently pass Earth in January 1974 at a distance of just 60 million miles.

All in all, the early discovery of Kohoutek’s object pointed to something intrinsically brighter than Halley’s Comet and probably something quite large, too. Elizabeth Roemer of the University of Arizona estimated that the nucleus could measure 20 miles or more in diameter, whilst other astronomers speculated that it might weigh many billions of pounds. Spectroscopic evidence for water-ice had been obtained and astronomers had reason to hope that hydrogen cyanide and methyl cyanide—both “polyatomic molecules,” previously only detected in intergalactic space, never in comets—were present in the nucleus. Consequently, in the late spring of 1973, Comet Kohoutek carried much promise. Its hyperbolic trajectory led to theories that it originated in the Oort Cloud, a spherical “shell,” far beyond the orbit of Neptune on the very edge of the Solar System, and as such it was suspected that this might be the latest in a series of very infrequent visits to the inner Solar System. Unlike the “worn-out” Halley’s Comet, the possibility that Kohoutek might be a “virgin” comet from the Oort Cloud sparked optimism that it would offer scientists a chance to study material unchanged from the primordial state and that it might be visually stunning.

The crew of America’s final Skylab mission—from left, Gerry Carr, Ed Gibson, and Bill Pogue—were the first humans to spend New Year in space in 1973-74. It was a time which offered the unique opportunity to observe Comet Kohoutek from above the sensible atmosphere. Photo Credit: NASA

A spectacular display of “outgassing” of this material and a brilliant, glittering tail as it neared the Sun was also increasingly likely. Sky and Telescope magazine predicted in May 1973 that it should be a conspicuous, naked-eye object of first magnitude or brighter, whilst other writers expected it to rival or even surpass the best views of Halley’s Comet. It was predicted that by early 1974, after perihelion, Kohoutek’s tail would be a fully grown and shimmering “streamer,” extending across maybe one-sixth of the night sky. In such an eventuality, exulted Harvard astronomer and comet specialist Fred Whipple, it might “well be the comet of the century.”

Not everyone was convinced, however. Many observers acknowledged that comets were notoriously unpredictable, and even The New York Times warned that Kohoutek might not live up to its billing, but none of this deterred the sky-watchers of 1973. Kohoutek shows were held in planetariums around the world, binocular and telescope purchases picked up and escalated at an exceptionally brisk pace—one company even announcing a 200 percent profit in its sales—and the luxury liner QE2 sailed from New York with 1,700 passengers on a special “comet cruise.” New York’s Hayden Planetarium planned a spectacular, six-day “Flight of the Comet” aboard a chartered Boeing 747, in time for the January 1974 perihelion, when Kohoutek was expected to reach maximum visibility. With candlelit (and comet-lit, it would seem) dinners offered for a total package of more than a thousand dollars per person, it was bound to be spectacular.

The makeshift Christmas tree built by astronauts Carr, Gibson and Pogue from old food containers and packaging also included a long-tailed star at its tip: Comet Kohoutek. Photo Credit: NASA

Yet as one journalist later remarked, the desire for success has a tendency to make us smug, and although Kohoutek would indeed be visible to the naked eye and would reach a magnitude of about -3, it did not live up to the hype. Today, it is generally thought not to be a pristine Oort Cloud comet, but a rocky object from the Kuiper Belt, a disk of material in the outer reaches of the Solar System, a “long-period” comet which will not again grace humanity with its presence for another 75,000 years. In fact, perhaps a little unfairly, Kohoutek’s name has become synonymous with spectacular duds. As for the unfortunate ocean voyagers, their thousand-dollar QE2 dinner tables actually brought them little more than disappointment, cloudy skies. and seasickness. …

Today, Kohoutek’s greatest claim to fame is that it appeared when it did: for America’s Skylab space station, with its powerful Apollo Telescope Mount (ATM), was in orbit and its second and third human crews were primed and ready for their missions of discovery. The timing could hardly have been better. Astronaut Karl Henize, himself an astronomer, summed up an excited spirit of optimism in the scientific community as spring burned into summer and summer cooled into fall in 1973. He saw Kohoutek, potentially, as an astronomical “Rosetta Stone”: an unexpected find, an incredibly fortuitous quirk of serendipity which might reveal vital clues to unlock the mystery of how the Sun and its attendant planets—and, by extension, ourselves—came into being more than 4.5 billion years ago.

By the fall of 1973, the third and final crew of Skylab—astronauts Gerry Carr, Ed Gibson, and Bill Pogue—were primed and ready to launch in November and spend as long as three months aboard the space station. The first few weeks of their mission were difficult, due to excessive overwork, but they clearly savored the appearance of Kohoutek: in addition to building a makeshift Christmas tree from food containers and packing material, they crafted a long-tailed star from silver foil and put it in pride of place at the top. In late November, Pogue began taking images of Kohoutek’s intrinsic brightness and commenced analyses of its coma and tail over the following days.

During two EVAs in late December 1973, Carr, Gibson and Pogue conducted observations of Comet Kohoutek. Photo Credit: NASA

On Christmas Day, Pogue and Carr spent seven hours outside on a spacewalk, during which time they were assigned the task of photographing the comet. They set up a camera, mounting it onto a strut and positioning it in such a way that Skylab’s ATM solar arrays blocked the Sun. Although neither man could physically “see” Kohoutek, they followed instructions from Mission Control. “The instructions were clear and it was a fairly easy job,” recalled Pogue in his NASA oral history. “I turned on the camera and I was finished.” Another EVA on 29 December, this time by Carr and Gibson, conducted more observations using a far ultraviolet camera provided by the Naval Research Laboratory.

Like many disappointed observers back on Earth, the astronauts could hardly describe the comet as brilliantly spectacular, but Carr was impressed, nonetheless. “It was so faint,” he told the NASA oral historian, “that we really had to work to find it. Once we did find it, we observed a gorgeous thing: small, faint, but gorgeous.” Still, although he and Gibson shot as much film as they could during their three and a half hours outside, they privately doubted that it was sensitive enough to record sufficiently good data. Over the next few days, from inside the workshop, the best results came from the ATM’s coronagraph … and, interestingly, from a series of pencil sketches by Gibson himself, today enshrined in the Smithsonian.

This image of Comet Kohoutek was acquired by a member of the final Skylab crew, 40 years ago. Photo Credit: NASA

With the dawn of the New Year, 1974, much of the comet-hunting on the ground had come to an end, and there was disappointment that Kohoutek had not lived up to its media-hyped billing. Journalists started calling it the “Flop of the Century,” ignoring the scientific yield and focusing only on its brightness as a marker of significance. In reality, the fault lay fairly and squarely upon their shoulders; for it was the media which falsely treated Kohoutek as a sure thing. In March 1974, Sky & Telescope glumly told its readers that, whilst professional astronomers were jubilant with their observations, “the general public wondered what had happened to the spectacle promised by the news media.”

Source: https://www.americaspace.com/2013/08/10/the-science-of-skylab-a-long-haired-visitor-part-1/
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 09, 2019, 14:03
Of Dentists, Urine Spills and Chicken Bones: A Space Station Test on Earth
By Ben Evans, on August 18th, 2012 [AS]

Clad in flight suits and masks, Bob Crippen, Bill Thornton and Karol ‘Bo’ Bobko receive well wishes from mission managers ahead of their entrance into the SMEAT chamber on 26 July 1972. Photo Credit: NASA

By the beginning of the 1970s, sideburns and hair were growing steadily longer, but NASA’s ability to execute longer space missions had experienced stunted growth. None of the Apollo lunar voyages were expected to spend more than two weeks away from Earth and the longest single American flight – Gemini VII in December 1965 – had lasted a little under 14 days. With the Skylab space station, it was hoped to press the envelope by having three teams of astronauts spend between one and three months in orbit. The Soviets had gotten the long-duration ball rolling, with an 18-day Soyuz mission in June 1970 and a three-week flight to their Salyut 1 station in the summer of the following year. It was already known that spending months of isolation in the most hostile environment ever visited would demand intense physical and psychological preparedness…and NASA decided that the best way to achieve that preparedness was by running a space station on the ground.

Plans for such a mission were laid in August 1970 between Dale Myers, NASA’s associate administrator for manned spaceflight, and Bob Gilruth, the head of the Manned Spacecraft Center in Houston, later to become the Johnson Space Center. They were responding to concern from physicians that microbial populations might experience changes with three men confined in close quarters, which might cause flare-ups of bacterial infection. Within weeks, a test plan had been formulated. It focused on experiment procedures, a functional evaluation of Skylab equipment and providing baseline medical data.

Original hopes to use two full-size Skylab mock-ups were too expensive and it was decided to run the test in the Crew Systems Division’s altitude chamber, located in Building 7 at the Manned Spacecraft Center. Early plans called for a 28-day test in September 1971 and a 56-day run, beginning in November. Each one would feature the operation of Skylab experiments, primarily medical in nature, including lower-body negative pressure, blood volume and body mass, vestibular function, metabolic activity and mineral balance. Two teams of volunteers (not necessarily astronauts) would participate in the tests, which were designed to mimic conditions aboard Skylab as closely as possible. Following the extraction of the first ‘crew’ from the chamber, a 30-day debriefing was planned. Its results would help to prepare the second crew for their mission. These mock ‘flights’ would be known as the Skylab Medical Experiments Altitude Test (SMEAT).

The chamber itself had already been extensively man-rated. More than 20 feet in diameter and 20 feet high, it was a two-floored stainless steel structure with more than a dozen viewing ports, several penetration bulkheads and a pair of airlocks. It contained closed-circuit television equipment and a closed-loop system to heat or cool its oxygen-nitrogen atmosphere, together with channels for communications, lighting, oxygen supplies and fire suppression systems. For the purposes of SMEAT, only one floor would be used, although the other was available for relaxation. The wardroom and waste management facilities were partitioned, as they would be on Skylab, but the remainder of the chamber was modified to accomplish the medical objectives. Simulated lighting, caution-and-warning devices and communications (through a Capcom and, due to the limitations of tracking, available only 20 percent of the time) added to the sense of realism.

Although none of the SMEAT crew would ever inhabit an orbital space station, they would each fly the Space Shuttle…and carried a wealth of expertise in space station design and development. Bob Crippen (left) and Karol ‘Bo’ Bobko (right) had been selected for the Air Force’s ill-fated Manned Orbiting Laboratory project, whilst Bill Thornton (centre) had worked on Skylab issues and was intimately involved in several of its scientific experiments. Photo Credit: NASA

In December 1970, the 28-day test was dropped and it was decided to perform a single, 56-day evaluation. Original plans to use volunteers were dropped in favour of astronauts and Bob Crippen, Karol ‘Bo’ Bobko and physician Bill Thornton were selected in June 1971 for a scheduled start date in July of the following year. In fact, NASA’s formal report on SMEAT, published in October 1973, noted that the “use of astronauts was considered desirable, since this would [ensure] a general comparability of background, skills and motivation…[with] subsequent Skylab crews”. In a NASA oral history interview, Bobko recalled that the ‘selection’ actually came from a drawing of straws, whilst Crippen felt that SMEAT was “the best job available” to an astronaut who was years away from a real flight. For his part, Thornton had already worked on Skylab – he was one of the principal investigators for its small-mass measurement device, to be used for weighing specimens in flight – and his two comrades had previously worked on the Air Force’s Manned Orbiting Laboratory project before joining NASA. Consequently, all three had experience in the station design process.

During the year before the test, Crippen, Thornton and Bobko participated in the design and layout of the SMEAT chamber and began practicing with the medical equipment in the spring of 1972. In a very real sense, their training regime matched the actual training of a Skylab crew, with equipment and maintenance briefings, bench checks, crew compartment fit and function tests and summaries of emergency procedures. Field trips to Air Force medical installations and regional hospitals offered them a thorough understanding of diseases of the eyes, head, cardiovascular, pulmonary and musculoskeletal systems and even gave them the chance to practice treatments. During the course of that year, each man spent in excess of 500 hours training for SMEAT, more than a hundred more than scheduled.

Their preparation for ‘medical emergencies’ even included dental work. “The plan was…to make sure that the crews could deal with…minor medical emergencies,” recalled Crippen in his NASA oral history, “and part of that was to send us off to dentistry school. We ended up in San Antonio at the Air Force hospital.”

On one occasion, a young man in his late teens came to see them. His teeth were in terrible shape. Two needed to be extracted and Crippen and Bobko asked the dentist if he was going to remove them.

“No,” came the reply. “You guys can do it.”

The astronauts exchanged glances. The patient looked nervous.

“But I did the novocaine with the needle,” Crippen recalled, “and Bo flipped the tooth out, because it wasn’t in very firmly.”

The response from their patient?

“You guys are the best dentists I’ve ever been to!”

Crippen and Bobko kept quiet. The last thing they wanted to announce was that they were both military test pilots will absolutely no background in dentistry…

Crippen (left) and Thornton at work inside SMEAT. Photo Credit: NASA

Other practice was less satisfying, including CPR on a ‘Resuscitation Annie’ dummy. When Crippen’s turn came, he thumped the palm of his hand hard onto the dummy’s chest…so hard, in fact, that he broke his fifth metacarpal! “Everybody concluded they didn’t want to have a heart attack with me around,” he mused later.

On the morning of the SMEAT start date, 26 July 1972, Crippen, Thornton and Bobko underwent a medical examination and pre-breathing to purge nitrogen from their bloodstreams. (Crippen later recalled that these preparations were actually worse than the test itself.) Inside the chamber, one of their earliest observations was that the reduced-pressure atmosphere caused sound to appear further away and somewhat softer, requiring them to shout and becoming hoarse in the first few days. Also connected to the pressure was an inability to whistle, a temporary increase in abdominal gas and severe flatulence and a noticeable mildness of sneezing. Typical daily routines involved reveille at seven in the morning, work from nine until one in the afternoon, followed by a second work period from two until seven, after which they ate dinner. A review of their activities and 30 minutes of housekeeping capped off each day and after two hours of ‘personal recreation’ they bedded down at eleven each evening.

For recreation, Crippen and Bobko – who were, by now, also preparing to serve as support crew members on the Apollo-Soyuz mission – brushed up their Russian language skills. They also completed a training course on the Apollo command and service module, via a closed-circuit television link, and even did electronics courses, solar physics courses and commercial pilots’ study courses. It was their choice before entering the SMEAT chamber that they would fill their spare time in a ‘useful’ way…

Not all went to plan and problems with the bicycle ergometer caused it to quickly break down, prompting the crew to pass it out through the main airlock for repair. The urine system also leaked. “Most of us, and probably most of the Skylab guys, drank a lot of liquids,” Bobko said later, “and so produced more urine than they had anticipated and…[so they] collected the urine in a bag and homogenised that and took a sample off and froze it. Well, what would happen is that at two o’clock in the morning, you get up and the bag would be full…and so, here you are, just kind of groggy out of bed and have to change it out and the bags were not very strong. There was an occasion when we dropped one and it broke. You know how messy it is to drop a half-gallon of milk on the floor. You can imagine!” Humour aside, with the ‘real’ Skylab launch scheduled for May 1973, cleaning the urine spills took the men at least an hour. This was unacceptable, not least because hand-washing facilities and the availability of disinfectants aboard the workshop would be insufficient.

Ensnared by the torment of a strict medical protocol and endless experiments, the SMEAT crew – represented by Snoopy in this unofficial mission patch – completed a schedule of activities which would prove critical in enabling America’s first orbital space station. Image Credit: NASA

Life aboard SMEAT was by no means luxurious – the astronauts’ main comfort came from a set of sun-loungers, which they assembled each evening – and they found themselves surrendering much time to cleaning the toilet, the work area and the floors. A simulated Skylab shower was “delightful” to use, once every week, with all three men showering on the same day. Meals were typical Skylab fare: small cans which fitted into food trays with built-in heating elements. Strict recording of body intakes and wastes and blood samples were religiously kept for the medical experiments.

Yet, psychologically, they managed to maintain good relationships with each other and with the support staff, through a system of ‘gotchas’. One dastardly plan involved a handful of meat-free chicken bones, smuggled into the chamber…and a few collected hairballs of lint from their suits. The three men had become tired of the strict protocol associated with the medical experiments and felt that a few laughs would be triggered by creating the impression that they were not alone inside SMEAT. Their plan was to leave the chicken bones and a few hairballs on a used meal tray, pass it through the airlock, with a note telling the doctor how much the ‘cat’ had enjoyed the fresh meat…

Unfortunately, time constraints meant they could not execute the plan, but had the gotcha taken place the look of sheer horror on the test conductors’ faces, as several weeks of intense medical protocol were seemingly ruined, would certainly have been golden.

Leaving the chamber on 20 September 1972 – with Crippen and Bobko both sporting full beards – the men were full of praise for SMEAT. The mission had been an essential test of the requirements for long-duration missions – missions which continue to be performed aboard today’s International Space Station. Yet the medical experiments were the bane of the three men’s daily lives. Crippen, Thornton and Bobko actually produced a comical mission patch, with the dog Snoopy as its centrepiece, restrained by a particularly nasty leash to signify their torment. Their uncomfortable two months in the SMEAT chamber was dirty, smelly and frequently unglamorous…but provided crucial data to make the future Skylab missions infinitely more bearable.

Source: https://www.americaspace.com/2012/08/18/of-dentists-urine-spills-and-chicken-bones-a-space-station-test-on-earth/
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 10, 2019, 08:23
Misja ratunkowa Skylab (1972)
BY ADAM PIECH ON 6 WRZEŚNIA 2010 [Kosmonauta.net]

Rysunek przedstawiający budowę stacji kosmicznej Skylab (MSFC-75-SA-4105-2C)

28 lipca 1973 roku, załoga Skylab 3 złożona z Alana Beana, Jacka Lousmy oraz Owena Garriotta wystartowała z wyrzutni LC-39B znajdującej się w Centrum Kosmicznym Kennedy’ego na Florydzie i udała się do stacji kosmicznej Skylab, przebywającej już na orbicie okołoziemskiej. Pomimo ich numerycznego oznaczenia misji byli dopiero drugą załogą, która miała znaleźć się na pokładzie Skylaba – powodem była decyzja NASA, w wyniku której bezzałogowy start stacji kosmicznej w dniu 14 maja 1973 roku został oznaczony jako misja Skylab 1 i jednocześnie poprzedzał wizytę pierwszej załogi w misji Skylab 2.

Vance Brand i Don Lind, załoga misji ratunkowej Skylab

Podczas końcowego podejścia do amerykańskiej stacji kosmicznej, jeden z silniczków rakietowych systemu RCS zainstalowany na pokładzie pojazdu Apollo CSM (Crew and Service Module) zaczął przepuszczać hipergoliczny utleniacz – tetratlenek diazotu. Załoga zgodnie z procedurami postępowania w takich przypadkach wyłączyła uszkodzony zestaw silniczków (pojazd Apollo posiadała cztery poczwórne zestawy silniczków RCS) i zakończyła cumowanie z użyciem pozostałych trzech zespołów RCS bez żadnych dodatkowych problemów.

Schemat rozmieszczenia dodatkowych miejsc dla astronautów w kapsule ratunkowej CSM

Drugiego sierpnia awarii uległ jednak kolejny zestaw silniczków co budziło obawy, że za uszkodzenia obu jednostek RCS odpowiada skażony, niezwykle silny utleniacz. Gdyby tak było w istocie, wtedy pozostałe dwa zespoły silniczków RCS oraz główny silnik CSM mogły także zostać uszkodzone – choć wszystkie posiadały niezależne systemy dostarczania paliwa, to jednocześnie zawierały utleniacz z tej samej, przypuszczalnie wadliwej partii. Co więcej, jeśli wycieki tetratlenku diazotu nadal by się pojawiały, wtedy mogło by dojść do skażenia wnętrza samego modułu serwisowego CSM, a także uszkodzenia kolejnych znajdujących się tam układów. W przeciągu godzin NASA wprowadziła więc w życie wariację planu Kennetha Kleinknechta, Menadżera Programu Skylab, oraz Lawrence’a Williamsa z Apollo Spacecraft Program Office którzy opisali go rok wcześniej w trakcie piątego sympozjum na temat kosmicznych systemów ratunkowych, które odbyło się w Wiedniu.

W przedstawionej pracy, Kleinknecht i Williams zauważyli, że Skylab jako pierwszy umożliwiałby wykonanie misji ratunkowej w amerykańskim programie kosmicznym. Jednomiejscowy pojazd Merkury oraz dwumiejscowe Gemini były zbyt małe i ograniczone by wykorzystywać je jako pojazdy ratunkowe. Statki kosmiczne Apollo CSM natomiast posiadały pod tym względem znacznie większe możliwości, choć każdy przenosił tylko nieco więcej tlenu, wody i zapasów żywności by zapewnić funkcjonowanie trzyosobowej załogi w trakcie trwającej dwa tygodnie misji księżycowej. W przypadku gdyby Apollo CSM pozostałby na orbicie Księżyca – na przykład z powodu awarii silnika głównego – wtedy załoga zginęłaby na długo nim NASA byłaby w stanie wysłać misję ratunkową.

W przypadku Skylab, gdyby zaszła konieczność ewakuacji astronautów, wtedy mogliby oni wejść na pokład ich pojazdu CSM i powrócić na Ziemię w przeciągu dnia. Z drugiej jednak strony, gdyby statek kosmiczny Apollo z jakiegoś powodu przestał być zdatny do użytku w czasie gdy byłby zacumowany do przedniego portu cumowniczego stacji kosmicznej Skylab, wtedy astronauci byliby zmuszeni czekać na jej pokładzie na ratunek. Zapasy zebrane na stacji były jednakże odpowiednie, by umożliwić ratunek nawet w przypadku gdyby ostatnia z trzech planowanych misji załogowych zostałaby przedłużona. Powodem tego był fakt, że stację wysłano by z zapasem tlenu, żywności, wody i pozostałych materiałów tak, aby mogły one umożliwić ośmiomiesięczny pobyt trzyosobowej załogi na jej pokładzie, choć trzy zaplanowane wizyty załóg łącznie miały trwać jedynie pięć miesięcy w czasie gdy Kleinknecht i Williams zaprezentowali swoją pracę.

W międzyczasie NASA przygotowałaby do wystrzelenia ratunkowy pojazd Apollo CSM z dwuosobową załogą, który zacumowałby do bocznego węzła cumowniczego modułu Multiple Docking Adapter. Kleinknecht i Williams zaproponowali by CMS, który miał służyć w programie lotów jako pojazd rezerwowy dla trzech misji załogowych, został przystosowany do pełnienia roli pojazdu ratunkowego dla trzeciej załogi Skylab.

Kleinknecht i Williams oszacowali, że usunięcie zbędnych elementów z kapsuły mającej pełnić zadania ratunkowe, tak aby można było zrobić w niej miejsce na „sprzęt ratunkowy” zajęłoby około dnia. Na elementy ratunkowe, które znalazłby się na pokładzie kapsuły złożyłyby się dwa  dodatkowe miejsca dla astronautów, systemy przyłączy umożliwiające podłączenie dwóch dodatkowych skafandrów do systemów podtrzymywania życia oraz specjalna paleta w której umieszczone by zostały wyniki eksperymentów. Załoga misji ratunkowej zajmowałaby dwa miejsca po bokach typowego pojazdu Apollo, podczas gdy trójka astronautów przebywająca na stacji zajęłaby jedno wolne miejsce pośrodku oraz dwa nowe, specjalne miejsca, które zostałyby umiejscowione poniżej pierwszych, w miejsce usuniętych wcześniej schowków.

Zestaw ratowniczy zawierałby także specjalny element umożliwiający ręczne pozbycie się uszkodzonego pojazdu CSM, zwalniając tym samym port cumowniczy dla przyszłych lotów załogowych.

Choć czas potrzebny do zainstalowania zestawu ratunkowego byłby niewielki, to przygotowania wyrzutni LC-39B oraz ratunkowej misji pojazdu CSM na rakiecie Saturn IB zajęłoby znacznie więcej czasu. Po każdym starcie Saturna IB, zespół naziemny potrzebowałby około 48 dni na ponowne przygotowanie do lotu z wyrzutni 39B oraz przystosowania kolejnego pojazdu CSM i rakiety Saturn IB. Z tego względu jeśli misja ratunkowa byłaby konieczna zaraz na początku 28-dniowej, pierwszej misji Skylab, wtedy pobyt załogi na jej pokładzie zostałby przedłużony o 20 dni. Z drugiej jednak strony, jeśli misja ratunkowa zostałaby zatwierdzona później, wtedy przygotowania do kolejnego lotu CSM byłyby bardziej zaawansowane, choć rozpoczęłyby się później. Z tego względu misja ratunkowa CSM oraz Saturn IB wymagałaby nadal 28 dni przygotowań przed najwcześniejszym możliwym startem. W obu przypadkach załoga musiałaby zatem pozostać na pokładzie stacji kosmicznej przez dwukrotnie dłuższy czas niż pierwotnie zakładano.

Druga i trzecia misja Skylab były zaplanowane na 56-dniowy pobyt na stacji kosmicznej, w czasie gdy Kleinknecht i Williams zaprezentowali swoją pracę. Rozpoczęcie 48-dniowych przygotowań do misji ratunkowej na początku trwania tych wypraw oznaczałoby, że załogi powróciłyby na Ziemię przed planowanym czasem zakończenia ich pobytu na orbicie. W przypadku wystąpienia konieczności wprowadzenia planu ratunkowego pod koniec trwania misji załogowych, wtedy od momentu podjęcia decyzji do wystrzelenia kapsuły ratunkowej upłynęłoby około 10 dni.

Awaria drugiego zestawu silniczków RCS do której doszło drugiego sierpnia w trakcie drugiej wyprawy załogowej na pokład stacji Skylab wywołała burzę. NASA postanowiła przygotować zapasowy Apollo CSM (a nie Skylab 4) jako pojazd ratunkowy oraz wyznaczyła dwie osoby z zapasowej załogi misji Skylab 3 (Vance’a Branda oraz Dona Linda) do pełnienia roli jego pilotów. Jednakże tuż po uruchomieniu planu ratunkowego analiza utleniacza wykazała, że tetratlenek diazotu nie został skażony i że awarie obu jednostek silniczków RCS nie łączyła wspólna przyczyna, którą dałoby się wykryć. Testy wykazały także, że załoga Skylab 3 jest w stanie również manewrować swoim pojazdem nawet z wykorzystaniem tylko jednego zestawu silniczków RCS.

Choć przygotowania do ewentualnej misji ratunkowej kontynuowano, to 10 sierpnia NASA wydała pozwolenie załodze Skylab 3 na ich pełen 59-dniowy pobyt na pokładzie stacji orbitalnej. Ostatecznie astronauci powrócili na Ziemię bez żadnych dodatkowych incydentów w swoim własnym pojeździe CSM. Miało to miejsce 25 września 1973 roku.

David S.F. Portree
Beyond Apollo blog

Na podstawie:
Skylab Rescue Capability, Kenneth S. Kleinknecht and Lawrence G. Williams; paper presented at the Fifth Annual Space Rescue Symposium Organized by the Space Rescue Studies Committee of the International Academy of Astronautics, 23rd Congress of the International Astronautical Federation, Vienna, Austria, October 9-12, 1972.

Źródło: https://kosmonauta.net/2010/09/misja-ratunkowa-skylab/#prettyPhoto
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 11, 2019, 08:20
'Stronger Than Required': Remembering Skylab's End, 40 Years On
By Ben Evans, on June 23rd, 2019 [AS]

One of the final views of Skylab in orbit, as seen directly by human eyes, during the departure of the third crew in February 1974. The station, which began its slow descent back to Earth 40 years ago, this summer, was the largest single object ever launched into space. Photo Credit: NASA

Forty years ago, this summer, America’s first space station, Skylab, breathed its last and commenced a slow descent back to Earth, eventually to burn up in the atmosphere. The vast complex—a converted Saturn V S-IVB third stage, which remains the largest and most massive single object ever launched into orbit on a single booster (https://www.americaspace.com/2017/11/05/without-breaking-the-shell-50-years-since-the-saturn-vs-maiden-launch/)—had been launched in May 1973, but had endured near-calamity from the start: a troubled ascent had seen its micrometeoroid shield torn away, one solar array ripped off and another clogged with debris (https://www.americaspace.com/2018/05/20/attitude-control-game-remembering-skylabs-fateful-launch-45-years-ago/).

Once in space, the sterling efforts of three astronaut crews over the next nine months had brought Skylab back to life, repaired it and achieved spectacular scientific results. Hundreds of hours of solar and astronomical observations were made, together with dozens of Earth resources studies and a vast corpus of biomedical data aided our understanding of how the human body functions in space over long periods of time.

Launched in May 1973 atop the final Saturn V, the mission of Skylab almost ended before it had even begun. Photo Credit: NASA

But in the five years after the last crew departed Skylab in February 1974 (https://www.americaspace.com/2018/11/25/a-dumb-decision-remembering-the-final-mission-to-skylab-45-years-ago/) and the old station’s eventual demise in July 1979, it was virtually abandoned. Its atmosphere was remotely vented, most of its systems were shut down and it was established in a gravity-gradient stabilized attitude, still capable of responding to telemetry commands, but with a troublesome control moment gyroscope and erratic coolant loops there seemed little likelihood that Skylab would again be occupied.

As the decade wore on, the sole chance of saving the station was with the shuttle, which was targeted to undertake its maiden voyage in 1979. Solar activity and its effect upon the upper atmosphere assured many NASA managers that Skylab could endure until the early 1980s and plans were set in motion for a potential shuttle reboost. In September 1977, the space agency initiated a two-year program to build hardware and Martin Marietta was contracted to study the feasibility of fabricating a boxy Teleoperater Retrieval System (TRS), to be deployed by an early shuttle crew to remotely dock and either reboost Skylab or cause the station to deorbit safely over an uninhabited stretch of ocean. Delivery of the $26 million TRS was slated for August 1979, with launch targeted for September, on a mission which included veteran astronauts Fred Haise and Jack Lousma (https://www.americaspace.com/2018/03/11/to-fly-the-first-one-40-years-since-the-first-space-shuttle-crews/).

Years later, Lousma recalled what would have been a five-day flight. He and Haise would have maintained a position about 1,000 feet (300 meters) from Skylab, after which Lousma would have deployed the TRS with the shuttle’s robotic arm and maneuvered it “like a radio-controlled airplane” to dock at the station. “The mission had never been planned to begin with, so the shuttles didn’t have rendezvous radar,” he told the NASA oral historian. “Fred got busy and started getting that implemented and also developing rendezvous procedures. I worked with Martin Marietta [as] the lead on the development [of the TRS].” In many minds, however, the mission was a waste of time and money, with even then-NASA Administrator Robert Frosch considering the chances of pulling it off as only 50/50.

In March 1978, a “pool” of crew members were announced for the first four Orbital Flight Tests (OFTs) of the shuttle. Among them were Jack Lousma (third from left) and Fred Haise (fourth from left), who might in an alternate history have flown the salvage mission to Skylab. Photo Credit: NASA

What really spelled doom for Skylab in the summer of 1979 was a marked increase in solar activity and its effect upon Earth’s atmosphere. Early calculations predicted that increased atmospheric density would make the station’s orbit susceptible to drag, dropping by around 18 miles (30 km) in altitude by 1980, and faster in the years thereafter, before finally burning up around March 1983. However, as the next solar maximum period neared, NASA was cautioned that the Sun was more active than anticipated, with particularly intense sunspot activity.

Even if the mission to save Skylab did go ahead, it was a risky endeavor. “We knew that Skylab wasn’t just sitting there motionless, waiting to be docked with, but it was actually augering through the sky with a motion that made the nose of it wobble in a circle,” Lousma reflected later. “When we designed the [TRS] booster package, it had to be capable of being flown so it could match that wobble of the docking port around a centerline. I had to fly that booster over there and match the circular motion and have enough power in the control system to make sure that could be done. We simulated [the] known wobble of the Skylab and made sure we could get to that, then we added to it and made a bigger wobble, so we could size the control system. That was part of the development.”

Two years later than planned, the Space Shuttle program got underway in April 1981. It was sadly too late, however, to salvage Skylab. Photo Credit: NASA

In the meantime, in February 1978, NASA made an initial contact with Skylab via the Bermuda tracking station and gradually, system by system, the aging hulk was brought back to life. However, with the shuttle’s maiden voyage planned for no sooner than late 1979, the chances of saving Skylab became increasingly remote. In December 1978, two separate test-stand failures of the Space Shuttle Main Engines (SSMEs) (https://www.americaspace.com/2015/11/24/nasa-contracts-with-aerojet-rocketdyne-to-restart-rs-25-engine-production-for-sls/) hammered the final nail into the coffin, delaying the first flight of the reusable orbiter until at least 1980. At about the same time, the North American Aerial Defense Command (NORAD) predicted the Skylab would deorbit in July or August 1979.

On 19 December, it was announced that NASA would henceforth focus its energies upon ensuring that Skylab could execute a controlled re-entry, without causing injuries or damage on the ground. Population density maps made this a troublesome effort, with a one-in-152 chance that someone might be hit by falling debris. The loss of the Soviet Union’s nuclear-powered Cosmos 954 satellite over Canada in January 1978 had upped the political stakes to avoid a disastrous re-entry and in January 1979 Skylab was placed into a solar-inertial, high-drag attitude.

British ITN News coverage of Skylab’s final descent. Video Credit: ITN/YouTube

During re-entry, and particularly during the so-called “terminal phase of decay”, at an altitude of around 77 miles (125 km), its stabilizing control moment gyros would be switched off. This would cause Skylab to tumble and the known lower drag effects associated with a tumbling configuration would result in a more predictable re-entry location and impact footprint. Other minor adjustments could also be made to its attitude to slightly increase or decrease atmospheric drag effects and thus lengthen or shorten the re-entry, but independent studies predicted that several large pieces of Skylab would probably survive the passage through the atmosphere.

The impact date, which was steadily refined by mid-June 1979 to sometime between 7-25 July, was expected to create a debris footprint 4,000 miles (6,400 km) long and 100 miles (160 km) wide. Finally, as July dawned, it was decided that the station would indeed be placed into an end-over-end tumbling motion during re-entry, thereby offering a more accurate prediction of its impact point. NORAD anticipated impact on the 12th and as controllers watched and listened, Skylab’s six years in orbit finally came to an end.

Artist’s concept of the shuttle rendezvous with Skylab and the engines of the Teleoperator Retrieval System (TRS) either reboosting the old station or enabling it to deorbit safely. As circumstances transpired, the Sun and the expansion of Earth’s atmosphere, together with delays to the shuttle program, solved the problem. Image Credit: NASA

In the official Skylab Reactivation Mission Report—published by NASA in March 1980—the majority of the break-up occurred between the altitudes of 37-60 miles (60-95 km): in sequence, the sole remaining solar panel was torn away by steadily increasing aerodynamic forces, after which the Apollo Telescope Mount (ATM) and the main part of Skylab were separated and the solar observatory’s windmill of arrays came apart. Final disintegration most likely occurred some 37 miles (60 km) above Earth. One of the earliest visual sightings was from an airline pilot, flying along Australia’s west coast, who reported an intense fireworks show, as multiple streaks of debris snaked across the sky.

“The actual vehicle was stronger than the specs required,” wrote David Hitt, Owen Garriott and Joe Kerwin in their seminal work on Skylab, Homesteading Space. “It held together longer than was calculated, breaking up over the Indian Ocean. Most of the debris fell harmlessly into the water, but some chunks fell in Western Australia, along a line from south to northeast of Perth.” It was a sad end for a program which had for a few years in the early-mid 1970s placed the United States ahead of the Soviet Union in terms of long-duration spaceflight; with its three crews having logged 28 days, 59 days and 84 days in orbit.

Source: https://www.americaspace.com/2019/06/23/stronger-than-required-remembering-skylabs-end-40-years-on/
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 11, 2019, 23:27
The Day Skylab Crashed to Earth: Facts About the First U.S. Space Station’s Re-Entry
The world celebrated, feared and commercialized the spectacular return of America's first space station.
JUL 11, 2012  ELIZABETH HANES [history.com]

1. Skylab was made to go up but not to come back down.

The space station known as Skylab was designed as an orbiting workshop for research on scientific matters, such as the effects of prolonged weightlessness on the human body. Because the project represented the next step toward wider space exploration, NASA threw itself into successfully putting Skylab in orbit. Unfortunately, the agency spent far less time and energy planning how to gracefully bring the space station back to Earth at the end of its mission. Even though Skylab was devised for just a nine-year lifespan, NASA failed to build in any control or navigation mechanisms to return the orbiter to terra firma. Doing so would have “cost too much,” administrator Robert Frosch said at the time. This lack of preparation presented a problem in late 1978, when NASA engineers discovered the station’s orbit was decaying rapidly. Skylab had become a 77-ton loose cannon. As word spread of the impending uncontrolled crash of the space station, Congress and the public demanded to know how NASA intended to avoid human casualties from the potential disaster. NASA responded with a plan to rehabilitate the laboratory-in-the-sky. The agency would use a new tool in development—the space shuttle—to boost Skylab into a higher orbit, thereby extending the lab’s operational life by about five years. After that, the station would simply continue to orbit as a shell, like the millions of tons of floating detritus now known as space junk. Funding and other snafus delayed the shuttle project, however, so NASA had to come up with a new plan. On July 11, 1979, with Skylab rapidly descending from orbit, engineers fired the station’s booster rockets, sending it into a tumble they hoped would bring it down in the Indian Ocean. They were close. While large chunks did go into the ocean, parts of the space station also littered populated areas of western Australia. Fortunately, no one was injured.

2. In June 1979, as the crash approached, Skylab-inspired parties and products were all the rage in the United States.

The imminent crash of Skylab midway through 1979 coincided with Americans’ declining confidence in their government. The stagnant economy and a second oil crisis dropped Congress’ approval rating to just 19 percent that year. Perhaps it’s no surprise, then, that many people took an irreverent view of the demise of Skylab, a government project. The Associated Press reported several instances of “Skylab parties” occurring across the United States. In St. Louis, Missouri, the “Skylab Watchers and Gourmet Diners Society” announced plans to view Skylab’s last orbit during a garden gathering at which “hard hats or similar protective headgear” were required. The Charlotte, North Carolina, News-Observer reported that a local hotel designated itself an “official Skylab crash zone (complete with painted target)” and was holding a poolside disco party. Mocking NASA’s inability to say precisely where Skylab would land, entrepreneurs across the country sold T-shirts emblazoned with large bullseyes. Another enterprising individual took a different tack and sold cans of “Skylab repellent.”

3. In Europe and Asia, fear of Skylab’s re-entry prompted unusual safety measures.

While Americans used Skylab’s looming demise as an excuse to party in June 1979, people in other countries didn’t take things quite so lightly. Initially, NASA could not specify when or where Skylab would come down, though the agency mapped out a potential debris field that spanned about 7,400 kilometers across the Indian Ocean and Australia. Even those who lived outside the projected debris footprint were nervous, however. The unexpected fiery crash in January 1978 of a Soviet satellite in northern Canada had scattered enriched uranium across a wide swath of grassland, and people around the globe feared a similar outcome from the Skylab impact—even though the space station contained no radioactive components. Few people felt reassured by NASA’s statement that the risk of human injury from the event was just “one in 152.” After NASA pinpointed the re-entry date as July 11, Scotland’s Glasgow Herald reported, “Worried holidaymakers in Devon [England] are taking no chances—they plan to sit out the morning in an old smuggler’s cave.” In Brussels, authorities planned to sound as many as 1,250 air raid-type sirens in the event that Skylab rained wreckage across the bucolic Belgian countryside.

4. An Australian youth profited handsomely from the Skylab crash, thanks to an American newspaper.

Beginning in June of 1979, as Skylab’s re-entry approached, many American newspapers jokingly proposed “Skylab insurance,” which would pay subscribers for death or injury caused by flying orbiter fragments. The San Francisco Examiner went one step further, offering a $10,000 prize to the first person to deliver a piece of Skylab debris to its office within 72 hours of the crash. Knowing the orbiter wasn’t coming down anywhere near the continental United States, the newspaper felt it was making a safe bet. It didn’t count on news of the bounty traveling all the way to Australia. There, 17-year-old Stan Thornton of tiny Esperance awoke to the commotion when Skylab broke apart in the atmosphere and pelted his house with space station fragments. Thinking quickly, he grabbed a few charred bits of material from his yard, hopped on a plane without so much as a passport or suitcase and made it to the Examiner’s office before the deadline. The newspaper good-naturedly paid out the award.

5. You won’t find the biggest and best pieces of Skylab wreckage in the United States. For that, head to the outback.

Those who remember the Space Shuttle Challenger tragedy of 1986 recall how diligently NASA searched for pieces of the vehicle and tried to ensure none were taken as “souvenirs.” More recently, when a notebook containing the handwritten calculations of Apollo 13’s James Lovell went up for auction, NASA stepped in to assert ownership of the item before reversing its decision and allowing Lovell to sell it. So it may seem odd that very few large pieces of Skylab debris reside in museums in the United States. Instead, space memorabilia enthusiasts must travel to the far-flung reaches of southwestern Australia, where several museums contain pieces of the orbiting space laboratory. The Balladonia museum houses a pair of large pieces of sheet metal from the orbiter. One is emblazoned with “SKYLAB” in red letters, while the other piece is labeled “Airlock/Danger.” The Esperance, Australia, museum features two chunks of a Skylab oxygen tank; the smaller one was dug up by a rancher in 1990.

6. It’s possible to own a piece of Skylab debris today.

Although today NASA claims any fragment of Skylab is the property of the United States, the agency didn’t enforce ownership at the time the space station crash-landed. In fact, NASA officials at Marshall Space Flight Center examined a number of specimens provided by the Australians who discovered them, mounted the items on plaques attesting to their authenticity and returned them to their finders. Newspaper accounts of the day noted that the United States could, under international treaties, claim the debris, but chose to adopt a finders-keepers approach instead. Many Australian prospectors who uncovered Skylab artifacts never reported the finds to authorities after tales of confiscated booty made the rounds. Because the orbiter almost completely burned up on re-entry, the majority of its remnants consist of very small shards. A popular method of capitalizing commercially on the crash at the time seems to have been encasing these items in Lucite for preservation and then selling them. These and other items, such as purported Skylab toothpaste and canned meals, can be purchased at various online auction sites.

Source: https://www.history.com/news/the-day-skylab-crashed-to-earth-facts-about-the-first-u-s-space-stations-re-entry
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 11, 2019, 23:27
The Day Skylab Crashed to Earth
Dave| Jul 7th, 2017 [davidreneke.com]

Skylab floats above Earth in February 1974. (NASA)

The space station known as Skylab was designed as an orbiting workshop for research on scientific matters, such as the effects of prolonged weightlessness on the human body. It was successful.

Because the project represented the next step toward wider space exploration, NASA threw itself into successfully putting Skylab in orbit. Unfortunately, the agency spent far less time and energy planning how to gracefully bring the space station back to Earth at the end of its mission.  This week marks 38 years since Skylab fell, on 11 July 1979. Here’s how it all unfolded…

Skylab was launched by NASA in 1973, and was manned by teams of astronauts as it orbited the earth. It collected vast amounts of data and images before being abandoned in space in 1974.

In 1979, NASA realised that Skylab was starting to break up and would re-enter the earth atmosphere, but they were unable to control Skylab’s path, nor could they predict exactly where the pieces might land.

The majority of the spacecraft burnt up in the atmosphere but parts of it fell in Western Australia, like this one picked up by a local resident.

The imminent crash of Skylab midway through 1979 coincided with Americans’ declining confidence in their government. The stagnant economy and a second oil crisis dropped Congress’ approval rating to just 19 percent that year. Perhaps it’s no surprise, then, that many people took an irreverent view of the demise of Skylab, a government project. The Associated Press reported several instances of “Skylab parties” occurring across the United States.

1. In St. Louis, Missouri, the “Skylab Watchers and Gourmet Diners Society” announced plans to view Skylab’s last orbit during a garden gathering at which “hard hats or similar protective headgear” were required. The Charlotte, North Carolina, News-Observer reported that a local hotel designated itself an “official Skylab crash zone (complete with painted target)” and was holding a poolside disco party. Mocking NASA’s inability to say precisely where Skylab would land, entrepreneurs across the country sold T-shirts emblazoned with large bullseyes. Another enterprising individual took a different tack and sold cans of “Skylab repellent.”

2. In Europe and Asia, fear of Skylab’s re-entry prompted unusual safety measures.
While Americans used Skylab’s looming demise as an excuse to party in June 1979, people in other countries didn’t take things quite so lightly. Initially, NASA could not specify when or where Skylab would come down, though the agency mapped out a potential debris field that spanned about 7,400 kilometers across the Indian Ocean and Australia. Even those who lived outside the projected debris footprint were nervous, however.

The unexpected fiery crash in January 1978 of a Soviet satellite in northern Canada had scattered enriched uranium across a wide swath of grassland, and people around the globe feared a similar outcome from the Skylab impact—even though the space station contained no radioactive components. Few people felt reassured by NASA’s statement that the risk of human injury from the event was just “one in 152.” After NASA pinpointed the re-entry date as July 11, Scotland’s Glasgow Herald reported, “Worried holidaymakers in Devon [England] are taking no chances—they plan to sit out the morning in an old smuggler’s cave.” In Brussels, authorities planned to sound as many as 1,250 air raid-type sirens in the event that Skylab rained wreckage across the bucolic Belgian countryside.

3. An Australian youth profited handsomely from the Skylab crash, thanks to an American newspaper.
Beginning in June of 1979, as Skylab’s re-entry approached, many American newspapers jokingly proposed “Skylab insurance,” which would pay subscribers for death or injury caused by flying orbiter fragments. The San Francisco Examiner went one step further, offering a $10,000 prize to the first person to deliver a piece of Skylab debris to its office within 72 hours of the crash. Knowing the orbiter wasn’t coming down anywhere near the continental United States, the newspaper felt it was making a safe bet.

It didn’t count on news of the bounty traveling all the way to Australia. There, 17-year-old Stan Thornton of tiny Esperance awoke to the commotion when Skylab broke apart in the atmosphere and pelted his house with space station fragments. Thinking quickly, he grabbed a few charred bits of material from his yard, hopped on a plane without so much as a passport or suitcase and made it to the Examiner’s office before the deadline. The newspaper good-naturedly paid out the award.

4. You won’t find the biggest and best pieces of Skylab wreckage in the United States. For that, head to the outback.
Those who remember the Space Shuttle Challenger tragedy of 1986 recall how diligently NASA searched for pieces of the vehicle and tried to ensure none were taken as “souvenirs.” More recently, when a notebook containing the handwritten calculations of Apollo 13′s James Lovell went up for auction, NASA stepped in to assert ownership of the item before reversing its decision and allowing Lovell to sell it. So it may seem odd that very few large pieces of Skylab debris reside in museums in the United States.

Instead, space memorabilia enthusiasts must travel to the far-flung reaches of southwestern Australia, where several museums contain pieces of the orbiting space laboratory. The Balladonia museum houses a pair of large pieces of sheet metal from the orbiter. One is emblazoned with “SKYLAB” in red letters, while the other piece is labeled “Airlock/Danger.” The Esperance, Australia, museum features two chunks of a Skylab oxygen tank; the smaller one was dug up by a rancher in 1990.

5. It’s possible to own a piece of Skylab debris today.
Although today NASA claims any fragment of Skylab is the property of the United States, the agency didn’t enforce ownership at the time the space station crash-landed. In fact, NASA officials at Marshall Space Flight Center examined a number of specimens provided by the Australians who discovered them, mounted the items on plaques attesting to their authenticity and returned them to their finders. Newspaper accounts of the day noted that the United States could, under international treaties, claim the debris, but chose to adopt a finders-keepers approach instead.

Many Australian prospectors who uncovered Skylab artifacts never reported the finds to authorities after tales of confiscated booty made the rounds. Because the orbiter almost completely burned up on re-entry, the majority of its remnants consist of very small shards. A popular method of capitalizing commercially on the crash at the time seems to have been encasing these items in Lucite for preservation and then selling them. These and other items, such as purported Skylab toothpaste and canned meals, can be purchased at various online auction sites.

Source: History
Source: https://www.davidreneke.com/the-day-skylab-crashed-to-earth/
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 11, 2019, 23:59
Skylab Debris Hits Australian Desert; No Harm Reported

President Sends a Note of Apology--Craft Was Shifted for Re-entry
By RICHARD D. LYONS [movies2.nytimes.com]


Image Provided by UMI

Washington, July 11--The Skylab space station, at 77 tons the largest object ever orbited, flashed through the atmosphere and disintegrated in a blaze of fireworks over the Indian Ocean today, showering tons of debris across the Great Australian Desert, one of the world's most remote places.

Officials of the National Aeronautics and Space Administration estimated tonight that the area of re-entry into the earth's atmosphere began over the north Atlantic and that disintegration began over Ascension Island in the south Atlantic.

Many accounts of sighting of debris have filtered from the sparsely populated desert region, but there have been no reports of either injury or property damage. Should either occur, the United States is bound by treaty to indemnify those hurt.

Carter Sends Apology

President Carter sent the Australians a message of apology and proferred assistance, saying:

"I was concerned to learn that fragments of Skylab may have landed in Australia. I am relieved to hear your Government's preliminary assessment that no injuries have resulted. Nevertheless, I have instructed the Department of State to be in touch with your Government immediately and to offer any assistance that you may need."

The threat that the disintegrating space station could rain havoc over a wide area had captured attention around the world in recent weeks as space agency controllers tried to predict and control when and where it would fall.

In making its 34,981st and final orbit of the earth, Skylab provided some anxious moments for space officials who had sought to steer it away from populous areas.

Debris Showered on Desert

Skylab re-entered the atmosphere several thousand miles farther down its orbital track than had been expected, and sent flaming debris onto the barren desert of Western Australia and, presumably, into the sea off southwestern Australia. Earlier, it had been expected to land in the ocean.

A decision to maneuver the craft as it moved closer to re-entry enabled it to fly safely over southern Canada and Maine, but may have been responsible for its Australia landing.

"We had a tougher bird than expected," said the Skylab project director, Richard G. Smith, several hours after re-entry had occurred at 12:37 P.M. Eastern daylight time. "We're glad it's down, but we would have liked to have seen it never sighted over Australia."

The decision on re-entry may be questioned in the days ahead. It involved a command to the spacecraft six hours before re-entry that put it into a sort of wobble, which was designed to extend its re-entry track by about 5,000 miles and 30 minutes.

The maneuver virtually assured that no debris would land on Canada and the northern United States, as had been feared late last night, but re-entry was prolonged so that chunks did shower down near Australia.

On the final pass shortly before noon, Skylab sped eastward over Portland, Ore., flew in an arc across the continent, descended over Maine and Nova Scotia, re-entered the atmosphere at 11:44 A.M., went farther down its track over the south Atlantic, and then started breaking up over Ascension Island at 12:11 A.M.

F.A.A. Closes Airspace

While Skylab was on this final pass, the Federal Aviation Administration closed a 150- mile-wide path of airspace east of Kennebunkport, Me., to minimize the possibility that debris might hit an aircraft. It later proved that the precautionary measure was unnecessary.

"We're in the last hour of the descent of Skylab," said the flight director, Charles Harlan, at the Johnson Space Center in Houston, just before disintegration.

First evidence that friction was heating up the satellite's surface--temperatures eventually reached several thousand degrees--came from the South Atlantic when the Ascension tracking station reported that telemetry data from the spacecraft were "becoming garbled and intermittent."

"The solar panels folded like a little duck's wings," said Bob Kapustka, a Skylab engineer at NASA's Marshall Space Flight Center in Huntsville, Ala.

Uneasiness at Headquarters

As the satellite headed beyond Ascension Island, around the Cape of Good Hope and into the Indian Ocean, a general uneasiness settled over the Skylab situation room at NASA headquarters across from the National Air and Space Museum along Independence Avenue in Washington.

Though not articulated, the fear was that through some gross miscalculation the spacecraft would continue to fly past Australia, over the Pacific and then re-enter somewhere near Vancouver Island in the Pacific Northwest.

To complicate the problem, while flying over the western regions of the Indian Ocean, Skylab was out of reach of civilian tracking stations, although as it neared Australia it was picked up by the radars of the secret spy satellite ground station at Pine Gap near the center of the country.

Then at 12:42 P.M., Eastern daylight time, officials of NASA announced that the easternmost edge of the debris footprint had landed at about 43 degrees south latitude and 106 east longitude, about 750 miles southwest of Perth on the west coast of Australia.

Estimate of Re-entry Point

Almost six hours later NASA officials set the final break-up point more than 1,000 miles farther east, about 31.8 degrees south latitude and 124.4 degrees east longitude.

"Entering debris believed to have been the heavier pieces of Skylab was sighted over the area of Western Australia," said a NASA announcement late this afternoon, adding: "No reports of accident or injury have been received.

If true, the larger pieces of the expected 26 tons of debris would then have fallen in the desert, an outback area largely inhabited by aborigines.

According to previous calculations by the space agency, the pieces, of which at least 500 would have weighed at least a pound, would land along a "footprint" about 4,000 miles long and 100 miles wide.

Predictions on Disintegration

But according to prior estimate, the largest pieces would land first on the easternmost end of the landing site because they had the greatest weight and thus the greatest momentum, at about 260 miles per hour. By contrast, the smaller pieces had been calculated to enter at a speed of perhaps 30 miles per hour.

The later calculations would have a footprint extending hundreds, perhaps even thousands of miles over the Australian continent.

Injury or property damage, in the event that it did happen, also would open to question the early-morning decision to wobble the spacecraft deliberately.

Mr. Smith said the decision was made about 3 A.M. after consultations with a group of experts, including Dr. Robert A. Frosch, the administrator of NASA.

"We made the decision on the basis of all the information we had, the best analysis we had, and I'd make that same decision again based on absolutely the same information," Mr. Smith said.

Noting that, "apparently, there has been some debris overfly of Australia," Mr. Smith conceded that a margin of error had crept into the calculations because of too little information being fed into the forecast computers at the start of the final orbit.

"We have been saying for weeks that we have an uncertainty around the point of predicted re-entry that is fairly large and this illustrates the point," Mr. Smith said. "The best information we had, the best information NORAD, everybody had predicted that it would come down before Australia." NORAD is the North American Air Defense Command, which supervises the tracking.

But for the wobble or tumble maneuver being made, Mr. Smith told newsmen later, there was a possibility that some debris might have struck North America.

'Worst-Case Situation'

"It was a worst-case situation," he said. "We were trying to prevent the creation of a worse condition than we started with."

For many weeks, NASA scientists had conducted a series of intricate calculations aimed at providing Skylab controllers with estimates of the numbers of people living beneath any given track of the vehicle. The final orbit was one of the best, since it was almost totally over ocean.

The final plunge thus ends the $2.6-billion Skylab project that began over a decade ago. The huge cylindrical space station was placed in orbit in 1973, and was visited by three parties of astronauts who carried out long scientific and medical experiments. The longest of the three-man groups stayed aloft for 84 days.

At present, NASA has no firm plans for the development of another space station like Skylab. Operations will center, starting next year, on the space shuttle, which blasts into orbit like a spacecraft and lands like an airplane.

Copyright 2010 The New York Times Company

Source: http://movies2.nytimes.com/learning/general/onthisday/big/0711.html#article
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 12, 2019, 07:51
40 Years Ago: Skylab Reenters Earth’s Atmosphere
July 11, 2019 [NASA]

                                                   Skylab Program patch

                         Composite of the three three-person crews who completed long-duration missions aboard the space station

Skylab (https://www.nasa.gov/feature/skylab-america-s-first-space-station/) was America’s first space station and first crewed research laboratory in space. The complex consisted of four major components: the Orbital Workshop (OWS), the Airlock Module (AM), the Multiple Docking Adapter (MDA), and the Apollo Telescope Mount (ATM). The Apollo Command and Service Module transported crews to and from Skylab and remained attached to the station throughout a crew’s occupancy. The OWS, converted from the upper stage of a Saturn rocket, served as the main working, living and sleeping compartment for the crews, and contained exercise equipment, a galley, and many of the scientific experiments, in particular for the life sciences studies. The AM enabled astronauts to conduct spacewalks, while the MDA included a prime and backup docking port for the Apollo spacecraft and housed the Earth Resources Experiment Package. The ATM contained telescopes for solar observations and four solar arrays for additional power. Once in orbit, the complex weighed 170,000 pounds, by far the heaviest spacecraft to date. An unprecedented research laboratory in space, Skylab contained scientific equipment to conduct research in a variety of disciplines. Astronauts aboard the station conducted 270 experiments in biomedical and life sciences, Earth observations, solar astronomy and materials processing. Among the most important were investigations on the astronauts’ physiological responses to long-duration space flight.

Illustration of the Skylab space station and its components as it would have appeared without the damage incurred at launch

On May 14, 1973, the final Saturn V rocket thundered off Launch Pad 39A at Kennedy Space Center to lift the Skylab space station into orbit. About 63 seconds into the mission, telemetry indicated premature deployment of the micrometeoroid shield, designed to protect the station from debris and also act as a thermal blanket. Debris from the torn shield jammed one of the station’s large solar arrays and aerodynamic forces tore the other panel completely off. Skylab made it to orbit, but it was underpowered and rapidly overheating.  Mission managers delayed the launch of the first crew by 10 days as engineers devised ways to save the station. Once on orbit, the Skylab-2 (https://www.nasa.gov/feature/skylab-2-mission-accomplished/) crew deployed a sunshade to cool the station and eventually free the stuck solar panel, saving the program. 

Launch of the Skylab space station on May 14, 1973. It was the final launch of a Saturn V rocket.

In all, three successive three-person crews spent 28 (https://www.nasa.gov/feature/skylab-2-mission-accomplished), 59 (https://www.nasa.gov/feature/skylab-3-a-record-59-days-in-space/) and 84 (https://www.nasa.gov/feature/45-years-ago-splashdown-of-third-and-final-skylab-crew/) days, respectively, aboard the space station, and as a platform for conducting scientific research Skylab proved its value.  The biomedical investigations carried out by the nine Skylab crewmembers provided our first glimpse into the effects of long-duration spaceflight on the human body and how to prevent some of the more deleterious effects. The ATM solar telescopes took more than 170,000 images for astronomers, while Earth scientists received 46,000 photographs. In nearly every science discipline, the astronauts exceeded the planned number of investigations. Of significant importance, having humans available for unplanned situations proved highly valuable, from the repair of the space station after its damage at launch, to being able to respond to unexpected events to increase the science return from the mission including observing new solar flares and a comet making a rare passage through the inner solar system. Managers, flight planners, and engineers used the Skylab experience to learn about how to live aboard and operate a long-duration crewed platform in space, passing on lessons learned to later programs like Shuttle-Mir and the International Space Station.

Skylab as it appeared to the final crew upon its departure.

Before leaving the station on Feb. 8, 1974, the Skylab-4 (https://www.nasa.gov/feature/45-years-ago-splashdown-of-third-and-final-skylab-crew) crew boosted it into a higher 269-by-283-mile orbit, in the hope that Skylab would remain in space until 1983. By then, the Space Shuttle would be flying and NASA hoped that astronauts could attach a rocket to the station to either boost it to a higher orbit or safely deorbit it over the Pacific Ocean. But delays in the Shuttle program and higher than expected solar activity resulting in increased atmospheric drag on the station ultimately thwarted those plans. It became apparent that Skylab would reenter in mid-1979, forcing NASA to devise plans to control its entry point as much as possible by adjusting the station’s attitude to adjust atmospheric drag.

Illustration of a proposed Skylab boost mission by the Space Shuttle.

Ground track of Skylab of its final orbits and the debris footprint in southwest Australia.

On July 11, 1979, during its 34,981st orbit around the Earth, engineers in Mission Control at the Johnson Space Center in Houston sent the final command to Skylab to turn off its control moment gyros, sending it into a slow tumble. This was the best that flight controllers could do to ensure that Skylab would not reenter over a populated area such as North America. They expected that it would begin its breakup over the southern tip of Africa and fall into the Indian Ocean. As it happened, the breakup occurred slightly later and while the majority of the debris that survived reentry did fall into the Indian Ocean, some pieces fell over sparsely populated areas of southern Western Australia. A museum in Esperance houses some of the recovered debris. Skylab Flight Director Charles S. Harlan said in a news conference after the event, “The surprise is over. No more suspense. Skylab is on the planet Earth.”

Mission Control in Houston during the Skylab reentry.

Managers and flight controllers monitor Skylab’s reentry.

The backup Skylab OWS is displayed at the Smithsonian’s  National Air and Space Museum (https://airandspace.si.edu/collection-objects/orbital-workshop-skylab-backup-flight-unit) in Washington, DC, while the Skylab training module is displayed at Space Center Houston.

The backup Skylab workshop on display at the Smithsonian’s National Air and Space Museum.

View inside the Skylab trainer on display at Space Center Houston. Credits: SCH, NASM.

John Uri
NASA Johnson Space Center

Source: https://www.nasa.gov/feature/40-years-ago-skylab-reenters-earth-s-atmosphere
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 12, 2019, 08:33
A space station crash landed over Esperance 40 years ago, setting in motion unusual events
ABC Esperance By Tom Joyner and Isabel Moussalli, Updated about an hour ago

The oxygen tank of the Skylab space station that fell over WA in 1979. PHOTO: The oxygen tank Pauline and Geoff Grewar found in 1993 hundreds of kilometres from Esperance. (Supplied: Geoff Grewar)

One morning in 1993, Geoff Grewar and his wife Pauline were flying a small aircraft over their farm property in Western Australia when they spotted a gleaming object in the scrub below.

At first, it looked like someone had parked their car among the bushes, but on closer inspection it resembled something more of an enormous capsule big enough for their grandkids to fit inside.

Puzzled, the former MP immediately called local authorities who said they wanted it collected with some urgency.

Mr Grewar did not realise it at the time, but the object — an oxygen tank from the unmanned space station Skylab — had until that point remained undisturbed for some 14 years.

The pair had stumbled upon what would be the single largest piece of NASA's ill-fated project that crashed to Earth one winter's night in 1979.

"It was so eerie," Mrs Grewar said.

"To find this oxygen tank that had come out of the sky, in the middle of vast open paddocks."

NASA's Skylab space station as seen from space. PHOTO: NASA's Skylab appeared in a "fiery apparition" over Esperance in the early hours of July 12, 1979. (Supplied: NASA)

'A fiery apparition'

Skylab, a bulky mass of metal and glass, had been launched in 1973 with the aim of providing an intimate view of the universe, and a platform for scientific research and experimentation in space.

But after six years in orbit, it slid off course and began a rapid and somewhat unpredictable descent back to Earth, gaining international media attention along the way.

In the weeks leading up to the crash, American newspapers speculated on where and when it might land.

A NASA official reportedly testified to US Congress there was a one in 152 chance of the plummeting spacecraft injuring someone.

So when it finally disintegrated in a fiery explosion over Esperance in the early hours of July 12, 1979, it caught locals off guard.

"We were just sipping the last of our coffee and we were startled by some sonic booms," said Brendan Freeman, a retired farmer who that night rushed onto his verandah and turned to the sky.

Retired farmer Brendan Freeman with his wife Fran at their home in Esperance, WA. PHOTO: Retired farmer Brendan Freeman had a clear view of Skylab's descent, which he likened to fireworks. (ABC Goldfields: Tom Joyner)

Mr Freeman and a group of others had gathered in anticipation of Skylab's re-entry, while others in Esperance flocked to Wireless Hill, a convenient lookout point in town.

"We watched this fiery apparition rocketing through the sky," he said.

"It was the best fireworks display you would ever see."

An international media storm

Local radio broadcasts had reported that re-entry was expected much earlier in the evening, around 10:30pm, and so most had turned in by the time the burning Skylab did appear in the night sky.

"Nearly half past midnight, bang, bang, bang — six fantastic sonic booms," said Merv Andre, who was the Esperance Shire president at the time.

"The doors rattled, and the wardrobe doors, and the windows."

What came next was a media storm.

In the days following, a party of NASA officials arrived in Western Australia to assess the situation and deal with the fallout.

In a press conference packed with Australian journalists, they fielded questions about what they had known of Skylab's path of descent.

In California, the San Francisco Examiner ran a competition to award $10,000 to the first person to bring a piece of Skylab back to their offices.

Astronaut Edward Gibson performs a space walk on Skylab space station. PHOTO: Astronaut Edward Gibson performs a space walk on the Skylab space station. (Supplied: NASA)

The competition prompted a frenzy among locals to find pieces of debris around the region.

It was ultimately won by an Esperance teenager called Stan Thornton, who made the journey to San Francisco with the financial help of a Perth radio station and Qantas.

There was barely enough time to get him a passport and visa for the trip, the Examiner reported the following day, nor did he have time to pack any clothes.

Littering fine issued to NASA

Before long it seemed that without warning, the small coastal community had been thrust onto the world stage.

An American TV station reportedly interviewed Qantas executives who told them the Skylab saga had done one good thing — it had reminded the world that Australia exists.

A makeshift workshop was set up for locals to bring in small pieces of Skylab for the officials to check for radiation with a Geiger counter.

One of the Shire's rangers at one point handed the NASA team a $400 fine for littering, meant as a tongue-in-cheek gesture.

The agency never paid it.

Two astronauts perform final checks before the first manned Skylab mission. PHOTO: Skylab remained in orbit around Earth for approximately six years in the 1970s. (Supplied: NASA)

Instead, three decades later, a radio broadcaster called Scott Barley from Barstow, California crowdfunded the outstanding penalty among his listeners and hand-delivered a novelty cheque to the Esperance Shire.

Today, the story has entered local folklore.

An enormous sign hangs from the exterior of the local museum in honour of the tale.

'We have used it shamelessly for publicity'

Few who were around four decades ago have ever forgotten the strange events of July 12, 1979, and many have their own story of where they were when it happened.

Some credit a boost to local tourism that has been sustained over the years since to the Skylab incident.

The Esperance Museum holds one of the world's largest collections of Skylab debris, which is on permanent display year-round.

Former Esperance Shire president Merv Andre gives a presentation on Skylab. PHOTO: Merv Andre was president of the Esperance Shire the night Skylab fell out of the sky. (ABC Goldfields: Tom Joyner)

Among its collection is the oxygen tank that Geoff and Pauline Grewar found in 1993, as well as a nitrogen tank and other assorted pieces of insulation and metal.

According to Mr Andre, the most miraculous part of the whole thing was that no one was injured — Skylab veered close to disaster but narrowly avoided it.

"Not a piece hit buildings or animals or people, nothing," Mr Andre said.

"One piece that ripped off the tank came down in the back lawn of a house, and it landed safely on the ground."

A competition run by the Esperance Shire this year saw the winner — a nine-year-old girl called Konii — interview via Skype Edward Gibson, a NASA astronaut who worked on Skylab.

Part of Skylab's legacy is an ongoing fascination with what happened, and why.

This year alone, it has inspired an art installation, a documentary film and a novel.

Most valuably though, said Lynda Horn of the Esperance Museum, Skylab's haphazard descent over WA later contributed to the success of the International Space Station.

"Skylab did put Esperance on the map," she said.

"It's great to have people coming to visit."

Mr Andre agreed.

"We have used it shamelessly for publicity," he said.

"It was a pretty wonderful thing to happen."

Source: https://www.abc.net.au/news/2019-07-12/four-decades-on-from-skylabs-descent-from-space/11249626
Tytuł: Odp: [gizmodo.com] This Is The Woman Who Replaced Skylab's Destroyed Sunshield
Wiadomość wysłana przez: Orionid w Lipiec 13, 2019, 06:26
Cloudbusting: The End of Skylab, 40 Years Later
by Emily Carney | Jun 29, 2019 [space.nss]


This Space Available
By Emily Carney

“It’s better to burn out than to fade away.” – Neil Young, “Hey Hey, My My (Into The Black)”

According to a previous blog post by This Space Available (https://space.nss.org/the-last-hurrah-skylabs-1978-1979-unmanned-mission/), when a proposed reboost mission carried out via Space Shuttle was ruled out as a possibility, NASA began to prepare for the inevitability that Skylab, in orbit since May 14, 1973, was coming down in mid-1979. Skylab’s operations during this period were dependent on the space station’s Apollo Telescope Mount Digital Computer (ATMDC), which was re-activated in March 1978, over four years after its last three-person crew had vacated. The computer system’s role now was to help control the station during its final months in orbit.

The NASA History book Living and Working in Space: The NASA History of Skylab stated that before the final crew had left in February 1974, they had boosted the station’s orbit: “Before undocking from Skylab, [mission commander] Gerald Carr had fired Apollo’s attitude-control thrusters for three minutes, nudging the cluster 11 kilometers higher, into an orbit of 433 by 455 kilometers [269 by 283 miles].” Following this boost, the ground further ensured Skylab was stably hibernating: “After the crew had returned to earth and the end-of-mission engineering tests were finished, flight controllers vented the atmosphere from the workshop, oriented the cluster in a gravity-gradient-stabilized attitude with the docking adapter pointed away from the earth, and shut down most of its systems.”

Skylab spent over four years in this mode, until it became clear that aerodynamic drag on the station needed to be minimized if it was going to “stay up” much longer. By early 1978, as the Solar Maximum year of 1980 approached, Skylab was predicted as coming down sooner than expected thanks to increased solar activity. Ironically, the very object of Skylab’s studies – the Sun – was aiding in its demise.

Enter the long-dormant ATMDC. The 1987 NASA publication Computers in Spaceflight: The NASA Experience related, “The original Skylab mission lasted 272 days with long unmanned periods. The reactivation mission, flown entirely under computer control, lasted 393 days.” During its human-helmed missions Skylab had flown mostly in solar inertial (SI) mode to ensure the best outcome for its battery of solar experiments, and as previously stated, had hibernated mostly in gravity-gradient mode. However, as Computers in Spaceflight explained, “…Engineers devised two new modes, end-on-velocity-vector (EOVV) and torque equilibrium altitude (TEA). EOVV pointed the narrow end of the lab in the direction of flight, minimizing aerodynamic drag on the vehicle. TEA could control the reentry, using the gravity gradient and gyroscopic torques to counterbalance the aerodynamic torque.”

Skylab 4’s Dr. Ed Gibson shortly after it was announced Skylab had reentered, July 11, 1979. Gibson was observing the reentry from the JSC control center in Houston. Screenshot used with permission from the film Searching For Skylab.

The book Homesteading Space establishes a timeline from the day it was apparent there was a problem (March 20, 1978) to the time Skylab entered EOVV (June 11, 1978), thanks to IBM who were responsible for the equations that reprogrammed the ATMDC. It was hoped that this mode could keep Skylab aloft through 1980. For a short time, the EOVV mode helped to minimize the space station’s downward trend, but in early 1979, Skylab would fall under NORAD’s scrutiny.

According to the Honeysuckle Creek website (https://www.honeysucklecreek.net/msfn_missions/Skylab/skylab_re-entry.html), “Toward the end of April, NASA Headquarters issued its first forecast of a reentry date calculated from NORAD’s model. On the 25th, when the workshop had fallen to about 320 kilometers [approximately 198 miles in altitude], NORAD estimated a probability of 50% that Skylab would come down by 19 June; there was a 90% chance that it would reenter between 13 June and 1 July. This format was used consistently for the rest of the waiting period, because it was impossible to give a more precise estimate until reentry had virtually begun. NASA and NORAD did exchange information and determined the different ways the two computer models treated data. NORAD made a fairly straightforward extrapolation based on recent observations, while NASA continuously took account of changing atmospheric density and the spacecraft’s drag profile as it came down.”

The website continued that the three-day “Death Watch” for Skylab began on Sunday, July 8, as Charles Harlan’s team in Houston kept a close eye on the station during its last days. With Skylab in TEA mode, it was decided to issue the “tumbling command” when the station was at an altitude of under 80 miles, with hopes it would avoid most landmasses. However, Homesteading Space underscored that the station “held together longer that was calculated, breaking up over the Indian Ocean.”

…And parts of Australia. The Honeysuckle Creek website painted a vivid portrait of the indignities the cluster underwent during its final moments, reporting, “[News bulletins] began 111 kilometers over Ascension Island in the Atlantic when the radar station there spotted the big solar panels begin to tear off as the lifeless hulk spun and twisted out of control. ‘It’s now out of range of all our tracking stations,’ said NASA, ‘The crash line is from Esperance in Western Australia to Cape York in Queensland. The chances of anybody coming to harm are minimal, but people are advised to stay indoors.’” The day was July 11, 1979, with NORAD calculating the impact time as 12:37 p.m. EDT.

Living and Working in Space paints another slightly chaotic scene: “Shortly before 1 p.m., the Washington control center received word that the area southeast of Perth, Australia, had indeed been showered with pieces. Spectacular visual effects were reported and many residents heard sonic booms and whirring noises as the chunks passed overhead in the early morning darkness. Officials waited anxiously for news of injury or property damage, but none came. Skylab was finally down and NASA had managed it without hurting anyone.” To this day, those curious enough to search can probably still find bits of Skylab lodged in parts of Western Australia.

One former Skylab resident observed its final moments with mixed emotions. As Skylab came down after making 34,981 revolutions, many with his presence aboard, Dr. Ed Gibson watched stoically in Houston’s control center. “Oh gosh!” he exclaimed. “I was unhappy we didn’t boost it [via Shuttle] further so we could use it again…I was unhappy about that. But I was happy I could be in the control room and actually watch it reenter.” Despite his feelings, he was careful to emphasize, “I was very proud of our program’s achievements.” Gibson would retire from his post at NASA in 1981, and the next long-duration American space station increment wouldn’t take place until 1995.

Featured image credit: A sign commemorates Skylab’s final orbit from the control center at Houston, Texas’ Johnson Space Center. Screenshot used with permission from the film Searching For Skylab (https://searchingforskylab.com/) (streaming information located in link).

Emily Carney is a writer, space enthusiast, and creator of the This Space Available space blog, published since 2010. In January 2019, Emily’s This Space Available blog was incorporated into the National Space Society’s blog. The content of Emily’s blog can be accessed via the This Space Available blog category (https://space.nss.org/category/this-space-available/).

Note: The views expressed in This Space Available are those of the author and should not be considered as representing the positions or views of the National Space Society.

Source: https://space.nss.org/cloudbusting-the-end-of-skylab-40-years-later/